What phenomenon is the flash of lightning? Lightning as a natural phenomenon. Rainbow as a physical phenomenon

Lightning is one of those natural phenomena that has long instilled fear in the human race. The greatest minds, such as Aristotle or Lucretius, sought to understand its essence. They believed that it was a ball consisting of fire and sandwiched in the water vapor of the clouds, and, increasing in size, it breaks through them and falls to the ground with a swift spark.

The concept of lightning and its origin

Most often, lightning is formed in areas that are quite large in size. The upper part can be located at an altitude of 7 kilometers, and the lower part can be only 500 meters above the earth's surface. Taking into account the atmospheric temperature, we can come to the conclusion that at a level of 3-4 km, water freezes and turns into ice, which, when colliding with each other, becomes electrified. Those that have the largest size receive a negative charge, and the smallest ones receive a positive charge. Based on their weight, they are evenly distributed in layers in the cloud. As they approach each other, they form a plasma channel, from which an electric spark called lightning is produced. It got its broken shape due to the fact that on the way to the ground there are often various air particles that form obstacles. And to get around them, you have to change the trajectory.

Physical description of lightning

A lightning discharge releases from 109 to 1010 joules of energy. Such a colossal amount of electricity is largely spent on creating a flash of light, which is otherwise called thunder. But even a small part of lightning is enough to do unthinkable things, for example, its discharge can kill a person or destroy a building. Another interesting fact suggests that this natural phenomenon is capable of melting sand, forming hollow cylinders. This effect is achieved due to the high temperature inside the lightning, it can reach 2000 degrees. The time it takes to hit the ground is also different; it cannot be more than a second. As for power, the pulse amplitude can reach hundreds of kilowatts. Combining all these factors, the result is the strongest natural discharge of current, which carries the death of everything it touches. All existing types of lightning are very dangerous, and encountering them is extremely undesirable for humans.

Thunder formation

All types of lightning cannot be imagined without a clap of thunder, which does not carry the same danger, but in some cases can lead to network failure and other technical problems. It occurs when a warm wave of air, heated by lightning to a temperature hotter than the sun, collides with a cold wave. The resulting sound is nothing more than a wave caused by air vibrations. In most cases, the volume increases towards the end of the roll. This occurs due to the reflection of sound from clouds.

What types of lightning are there?

It turns out that they are all different.

1. Linear lightning is the most common type. The electric boom looks like an upside-down, overgrown tree. Several thinner and shorter “shoots” extend from the main canal. The length of such a discharge can reach 20 kilometers, and the current strength can be 20,000 amperes. The speed of movement is 150 kilometers per second. The temperature of the plasma filling the lightning channel reaches 10,000 degrees.

2. Intracloud lightning - the origin of this type is accompanied by changes in electric and magnetic fields, and radio waves are also emitted. Such a boom is most likely to be found closer to the equator. In temperate latitudes it appears extremely rarely. If there is lightning in a cloud, then a foreign object that violates the integrity of the shell, for example, an electrified aircraft or a metal cable, can induce it to come out. The length can vary from 1 to 150 kilometers.

3. Ground lightning - this type goes through several stages. At the first of them, impact ionization begins, which is created at the beginning by free electrons, they are always present in the air. Under the influence of an electric field, elementary particles acquire high speeds and are directed towards the ground, colliding with the molecules that make up the air. Thus, electronic avalanches, otherwise called streamers, arise. They are channels that, merging with each other, cause bright, thermally insulated lightning. It reaches the ground in the form of a small staircase because there are obstacles in its path, and in order to get around them, it changes direction. The speed of movement is approximately 50,000 kilometers per second.

After the lightning has completed its path, it stops moving for several tens of microseconds, and the light weakens. After this, the next stage begins: repeating the traversed path. The most recent discharge exceeds all previous ones in brightness; the current in it can reach hundreds of thousands of amperes. The temperature inside the channel fluctuates around 25,000 degrees. This type of lightning lasts the longest, so the consequences can be devastating.

Pearl lightning

When answering the question about what types of lightning there are, one cannot lose sight of such a rare natural phenomenon. Most often, the discharge passes after the linear one and completely repeats its trajectory. Only in appearance it looks like balls located at a distance from each other and reminiscent of beads made of precious material. Such lightning is accompanied by the loudest and most booming sounds.

Ball lightning

A natural phenomenon when lightning takes the form of a ball. In this case, the trajectory of its flight becomes unpredictable, which makes it even more dangerous for humans. In most cases, such an electric lump occurs together with other types, but the fact of its appearance even in sunny weather has been recorded.

How it is formed This is the question most often asked by people who have encountered this phenomenon. As everyone knows, some things are excellent conductors of electricity, and it is in them that, accumulating their charge, the ball begins to emerge. It can also appear from the main lightning. Eyewitnesses claim that it simply appears out of nowhere.

The diameter of lightning ranges from a few centimeters to a meter. As for color, there are several options: from white and yellow to bright green, it is extremely rare to find a black electric ball. After a rapid descent, it moves horizontally, about a meter from the surface of the earth. Such lightning can unexpectedly change its trajectory and disappear just as suddenly, releasing enormous energy, which causes melting or even destruction of various objects. She lives from ten seconds to several hours.

Sprite lightning

More recently, in 1989, scientists discovered another type of lightning, which was called sprite. The discovery happened completely by accident, because the phenomenon is observed extremely rarely and lasts only tenths of a second. They are distinguished from others by the altitude at which they appear - approximately 50-130 kilometers, while other subspecies do not overcome the 15-kilometer limit. Sprite lightning is also distinguished by its huge diameter, which reaches 100 km. They appear vertical and flash in groups. Their color varies depending on the composition of the air: closer to the ground, where there is more oxygen, they are green, yellow or white, but under the influence of nitrogen, at an altitude of more than 70 km, they acquire a bright red hue.

Behavior during a thunderstorm

All types of lightning carry an extraordinary danger to human health and even life. To avoid electric shock, the following rules should be followed in open areas:

In this situation, the highest objects are at risk, so you should avoid open areas. To become lower, it is best to squat down and put your head and chest on your knees; in case of defeat, this position will protect all vital organs. Under no circumstances should you lie flat so as not to increase the area of possible impact.
Also, you should not hide under tall trees and unprotected structures or metal objects (for example, a picnic shelter) will also be undesirable shelter.
During a thunderstorm, you need to immediately get out of the water, because it is a good conductor. Once struck, a lightning bolt can easily spread to a person.
Under no circumstances should you use a mobile phone.
To provide first aid to the victim, it is best to perform cardiopulmonary resuscitation and immediately call the rescue service.

Rules of conduct in the house

There is also a danger of injury indoors.

If there is a thunderstorm outside, the first thing you need to do is close all the windows and doors.
All electrical appliances must be turned off.
Stay away from corded phones and other cables; they are excellent conductors of electricity. Metal pipes have the same effect, so you should not be near plumbing.
Knowing how ball lightning is formed and how unpredictable its trajectory is, if it does enter a room, you must immediately leave it and close all windows and doors. If these actions are impossible, it is better to stand still.

Nature is still beyond human control and poses many dangers. All types of lightning are, in essence, the most powerful electrical discharges, which are several times greater in power than all man-made current sources.

Introduction........................................................ ................................................... 3

1. Historical views on lightning.................................................... ... 4

2. Lightning................................................... ................................................... 6

Types of lightning........................................................ ....................................... 9

Physics of linear lightning............................................................ ..................... 9

The mystery of ball lightning……………………………………………...13

3. Discharges................................................... ............................................... 26

Types of discharges........................................................ ................................ 26

Spark discharge................................................... ........................... 26

4. Lightning protection................................................... .................................. 33

Conclusion................................................. ........................................ 37

List of references......................................................... 39

The choice of the topic of my essay is determined not only by personal interest, but also by relevance. The nature of lightning is fraught with many mysteries. When describing this rare phenomenon, scientists are forced to rely only on scattered eyewitness accounts. These meager stories and a handful of photographs are all that science has at its disposal. As one scientist stated, we know no more about lightning than the ancient Egyptians knew about the nature of stars.

Lightning is of great interest not only as a peculiar natural phenomenon. It makes it possible to observe an electrical discharge in a gaseous medium at a voltage of several hundred million volts and a distance between electrodes of several kilometers. The purpose of this essay is to consider the causes of lightning and study various types of electrical charges. The abstract also discusses the issue of lightning protection. People realized a long time ago what harm a lightning strike could cause, and they came up with protection against it.

Lightning has long been of interest to scientists, but even today we know only a little more about their nature than 250 years ago, although we were able to detect them even on other planets.

2. Historical views on lightning

Lightning and thunder were initially perceived by people as an expression of the will of the gods and, in particular, as a manifestation of God's wrath. At the same time, the inquisitive human mind has been trying for a long time to comprehend the nature of lightning and thunder, to understand their natural causes. In ancient times, Aristotle pondered this. Lucretius thought about the nature of lightning. His attempts to explain thunder as a consequence of the fact that “clouds collide there under the pressure of the winds” seem very naive.

For many centuries, including the Middle Ages, it was believed that lightning was fiery vapor trapped in the water vapor of clouds. Expanding, it breaks through them at the weakest point and quickly rushes down to the surface of the earth.

In 1752, Benjamin Franklin (Fig. 1) experimentally proved that lightning is a strong electrical discharge. The scientist performed the famous experiment with a kite, which was launched into the air as a thunderstorm approached.

Experience: A sharpened wire was fastened to the crosspiece of the snake; a key and a silk ribbon were tied to the end of the rope, which he held with his hand. As soon as the thundercloud was above the kite, the sharpened wire began to extract an electric charge from it, and the kite, along with the string, became electrified. After the rain wets the kite and the string, thereby making them free to conduct an electric charge, you can observe how the electric charge will “drain” when your finger approaches.

Simultaneously with Franklin, M.V. was studying the electrical nature of lightning. Lomonosov and G.V. Richman.

Thanks to their research, the electrical nature of lightning was proven in the mid-18th century. From that time on, it became clear that lightning is a powerful electrical discharge that occurs when clouds are sufficiently electrified.

Lightning is an eternal source of recharging the Earth's electric field. At the beginning of the 20th century, the Earth's electric field was measured using atmospheric probes. Its intensity at the surface turned out to be approximately 100 V/m, which corresponds to a total charge of the planet of about 400,000 C. The carrier of charges in the Earth's atmosphere are ions, the concentration of which increases with altitude and reaches a maximum at an altitude of 50 km, where under the influence of cosmic radiation an electrically conductive layer has formed - the ionosphere. Therefore, the Earth's electric field is the field of a spherical capacitor with an applied voltage of about 400 kV. Under the influence of this voltage, a current of 2-4 kA, the density of which is 1-12 A/m2, constantly flows from the upper layers to the lower ones, and energy is released up to 1.5 GW. And this electric field would disappear if there were no lightning! Therefore, in good weather, the electrical capacitor - the Earth - is discharged, and during a thunderstorm it is charged.

Lightning is a natural discharge of large accumulations of electrical charge in the lower layers of the atmosphere. One of the first to establish this was the American statesman and scientist B. Franklin. In 1752, he conducted an experiment with a paper kite, the cord of which had a metal key attached to it, and received sparks from the key during a thunderstorm. Since then, lightning has been intensively studied as an interesting natural phenomenon and because of the serious damage to power lines, houses and other structures caused by direct lightning strikes or lightning-induced voltages.

How to trigger a lightning strike? It is very difficult to study what will happen in an unknown place and when. And this is exactly how scientists studying the nature of lightning have worked for many years. It is believed that the thunderstorm in the sky is led by Elijah the prophet and we are not given to know his plans. However, scientists have long tried to replace Elijah the prophet by creating a conductive channel between a thundercloud and the earth. To do this, B. Franklin flew a kite during a thunderstorm, ending with a wire and a bunch of metal keys. By doing this, he caused weak discharges flowing down the wire, and was the first to prove that lightning is a negative electrical discharge flowing from the clouds to the ground. Franklin's experiments were extremely dangerous, and one of those who tried to repeat them, Russian academician G.V. Richman, died from a lightning strike in 1753.

In the 1990s, researchers learned how to create lightning without endangering their lives. One way to trigger lightning is to fire a small rocket from the ground directly into a thundercloud. Along its entire trajectory, the rocket ionizes the air and thus creates a conducting channel between the cloud and the ground. And if the negative charge at the bottom of the cloud is large enough, then a lightning discharge occurs along the created channel, all parameters of which are recorded by instruments located next to the rocket launch pad. To create even better conditions for lightning to strike, a metal wire is attached to the rocket, connecting it to the ground.

The cloud is a factory for the production of electrical charges. However, different “charged” dust can appear on bodies, even if they are made of the same material - it is enough for the surface microstructure to differ. For example, when a smooth body rubs against a rough one, both will become electrified.

A thundercloud is a huge amount of steam, some of which has condensed into tiny droplets or floes of ice. The top of a thundercloud can be at an altitude of 6-7 km, and the bottom can hang above the ground at an altitude of 0.5-1 km. Above 3-4 km, the clouds consist of ice floes of different sizes, since the temperature there is always below zero. These pieces of ice are in constant motion, caused by rising currents of warm air from the heated surface of the earth. Small pieces of ice are more easily carried away by rising air currents than large ones. Therefore, “nimble” small pieces of ice, moving to the top of the cloud, constantly collide with large ones. With each such collision, electrification occurs, in which large pieces of ice are charged negatively, and small ones - positively. Over time, positively charged small pieces of ice end up at the top of the cloud, and negatively charged large ones end up at the bottom. In other words, the top of a thunderstorm is positively charged and the bottom is negatively charged. Everything is ready for a lightning discharge, in which air breakdown occurs and the negative charge from the bottom of the thundercloud flows to the Earth.

Lightning is a “hello” from space and a source of X-ray radiation. However, the cloud itself is not able to electrify itself enough to cause a discharge between its lower part and the ground. The electric field strength in a thundercloud never exceeds 400 kV/m, and electrical breakdown in the air occurs at a voltage greater than 2500 kV/m. Therefore, for lightning to occur, something other than an electric field is needed. In 1992, Russian scientist A. Gurevich from the Physical Institute named after. P. N. Lebedev RAS (FIAN) suggested that cosmic rays - high-energy particles falling on the Earth from space at near-light speeds - could be a kind of ignition for lightning. Thousands of such particles bombard every square meter of the earth's atmosphere every second.

According to Gurevich's theory, a particle of cosmic radiation, colliding with an air molecule, ionizes it, resulting in the formation of a huge number of high-energy electrons. Once in the electric field between the cloud and the ground, the electrons are accelerated to near light speeds, ionizing their path and thus causing an avalanche of electrons moving with them towards the ground. The ionized channel created by this avalanche of electrons is used by lightning to discharge.

Recent studies have shown that lightning is a fairly powerful source of X-ray radiation, the intensity of which can be up to 250,000 electron volts, which is about twice that used in chest X-rays.

a) Most lightning occurs between a cloud and the earth's surface, however, there is lightning that occurs between clouds. All these lightnings are usually called linear. The length of a single linear lightning bolt can be measured in kilometers.

b) Another type of lightning is strip lightning (Fig. 2). In this case, the following picture appears as if several almost identical linear lightnings appeared, shifted relative to each other.

c) It was noticed that in some cases, a lightning flash disintegrates into separate luminous areas several tens of meters long. This phenomenon is called bead lightning. According to Malan (1961), this type of lightning is explained on the basis of a prolonged discharge, after which the glow would seem to be brighter in the place where the channel bends towards the observer observing it with its end facing him. And Youman (1962) believed that this phenomenon should be considered as an example of the “ping effect,” which consists of a periodic change in the radius of the discharge column with a period of several microseconds.

d) Ball lightning, which is the most mysterious natural phenomenon.

Linear lightning consists of several pulses quickly following each other. Each pulse is a breakdown of the air gap between the cloud and the ground, occurring in the form of a spark discharge. Let's look at the first impulse first. There are two stages in its development: first, a discharge channel is formed between the cloud and the ground, and then the main current pulse quickly passes through the formed channel.

The first stage is the formation of a discharge channel. It all starts with the fact that an electric field of very high intensity is formed at the bottom of the cloud - 105...106 V/m.

Free electrons receive enormous accelerations in such a field. These accelerations are directed downward, since the lower part of the cloud is negatively charged, and the surface of the earth is positively charged. On the way from the first collision to the next, the electrons acquire significant kinetic energy. Therefore, when they collide with atoms or molecules, they ionize them. As a result, new (secondary) electrons are born, which, in turn, are accelerated in the field of the cloud and then ionize new atoms and molecules in collisions. Whole avalanches of fast electrons appear, forming clouds at the very “bottom”, plasma “threads” - a streamer.

Merging with each other, the streamers give rise to a plasma channel through which the main current pulse will subsequently pass.

This plasma channel developing from the “bottom” of the cloud to the surface of the earth is filled with free electrons and ions, and therefore can conduct electric current well. He is called leader or more precisely step leader. The fact is that the channel is not formed smoothly, but in jumps - “steps”.

Why there are pauses in the leader’s movement, and relatively regular ones at that, is not known for sure. There are several theories of stepped leaders.

Taking into account stops along the way, it took the leader 10...20 ms to reach the ground at a distance of 1 km between the cloud and the earth's surface. Now the cloud is connected to the ground by a plasma channel that perfectly conducts current. The channel of ionized gas seemed to short-circuit the cloud with the earth. This completes the first stage of development of the initial impulse.

Second stage flows quickly and powerfully. The main current flows along the path laid by the leader. The current pulse lasts approximately 0.1 ms. The current strength reaches values of the order of A. A significant amount of energy is released (up to J). The gas temperature in the channel reaches . It is at this moment that the unusually bright light that we observe during a lightning discharge is born, and thunder occurs, caused by the sudden expansion of the suddenly heated gas.

It is important that both the glow and the heating of the plasma channel develop in the direction from the ground to the cloud, i.e. down up. To explain this phenomenon, let us conditionally divide the entire channel into several parts. As soon as the channel has formed (the leader's head has reached the ground), first of all the electrons that were in its lowest part jump down; therefore, the lower part of the channel first begins to glow and warm up. Then electrons from the next (higher part of the channel) rush to the ground; the glow and heating of this part begin. And so gradually - from bottom to top - more and more electrons are included in the movement towards the ground; As a result, the glow and heating of the channel propagate in the direction from bottom to top.

After the main current pulse has passed, there is a pause

lasting from 10 to 50ms. During this time, the channel practically goes out, its temperature drops to approximately , and the degree of ionization of the channel decreases significantly.

As stated above, the new leader follows the path that was blazed by the original leader. It runs all the way from top to bottom without stopping (1ms). And again a powerful pulse of the main current follows. After another pause, everything repeats. As a result, several powerful pulses are emitted, which we naturally perceive as a single lightning discharge, as a single bright flash (Fig. 3).

The Mystery of Ball Lightning

Ball lightning is absolutely not similar to ordinary (linear) lightning, either in its appearance or in the way it behaves. Ordinary lightning is short-lived; the ball lives tens of seconds, minutes. Normal lightning is accompanied by thunder; the ball is almost silent, there is a lot of unpredictable behavior in its behavior (Fig. 4).

Ball lightning asks us many riddles, questions to which there is no clear answer. At present, we can only speculate and make hypotheses.

The only method for studying ball lightning is the systematization and analysis of random observations.

Here is the most reliable information about ball lightning (BL)

1. The ball is a spherical object with a diameter of 5 ... 30 cm. The shape of the ball changes slightly, taking on a pear-shaped or flattened spherical shape. Very rarely, BL was observed in the shape of a torus.

2. The BL usually glows orange; cases of violet color have been noted. The brightness and character of the glow are similar to the glow of hot charcoal, sometimes the intensity of the glow is compared to a weak electric light bulb. Against the background of homogeneous radiation, brighter luminous areas (flares) appear and move.

3. The lifetime of the BL is from several seconds to ten minutes. The existence of a BL ends with its disappearance, sometimes accompanied by an explosion or a bright flash that can cause a fire.

4. CMM is usually observed during a thunderstorm with rain, but there is isolated evidence of the observation of CMM during a thunderstorm without rain. There have been cases of observations of CMM over water bodies at a significant distance from the shore or any objects.

5. The CMM floats in the air and moves along with air currents, but at the same time it can make “strange” active movements that clearly do not coincide with the movement of air.

When colliding with surrounding objects, the ball bounces off like a weakly inflated balloon or ends its existence.

6. Upon contact with steel objects, the ball is destroyed, and a bright flash lasting several seconds is observed, accompanied by scattering luminous fragments, reminiscent of metal welding. Upon subsequent inspection, steel objects turn out to be slightly melted.

7. CMM sometimes enters the room through closed windows. Most witnesses describe the penetration process as pouring through a small hole; a very small part of witnesses claim that CMM penetrates through intact window glass, while practically not changing its shape.

8. When the CMM briefly touches human skin, minor burns are recorded. Contacts resulting in a flash or explosion have resulted in severe burns and even death.

10. There is evidence of observation of the process of the emergence of BL from electrical outlets or operating electrical appliances. In this case, a luminous point first appears, which within a few seconds increases to a size of the order of 10 cm. In all such cases, the BL exists for several seconds and is destroyed with a characteristic bang without significant harm to the objects present and surrounding objects.

Most articles and reports about BL begin with information that the nature of BL is unknown, and a little further follows the statement that BL is plasma. Especially for authors who find it difficult to look into reference books and encyclopedias, I present the following selection.

“In a number of ways, plasma is very similar to a gas. It is both rarefied and fluid. In general, plasma is neutral, since it contains the same number of negatively and positively charged particles.”

“Plasma is a normal form of existence of matter at temperatures of the order of 10,000 degrees and above. Up to 100 thousand degrees it is cold plasma, and above it is hot.”

Containing plasma in a given open volume is a complex technical problem.

“Experiments at experimental thermonuclear installations are underway in different countries, but it has not yet been possible to achieve the required temperature and plasma retention time.” We are talking about a time not exceeding 1 s.

It is quite obvious that plasma in the air cannot create a spherical structure, much less maintain it for several minutes.

Let us formulate the main conclusions that can be drawn from the analysis of observations.

The density of the substance of ball lightning practically coincides with the density of air and usually only slightly exceeds it.

It is not for nothing that ball lightning tends to go down; the difference between the force of gravity and the buoyancy (Archimedean) force is compensated by convection air currents, as well as the force with which the atmospheric electric field acts on the lightning.

The temperature of ball lightning (not counting the moment of “explosion”) is only relatively slightly higher than the temperature of the surrounding air, apparently reaching only a few hundred degrees (presumably 500-600 K).

The substance of ball lightning is a conductor with a low work function of charges and therefore has the property of easily dissipating electrical charges accumulated in other conductors.

The contact of ball lightning with charged conductors leads to the appearance of short-term pulses of electric current, quite significant in strength and sometimes appearing at a relatively large distance from the point of contact. This causes fuses to blow, relays to trip, electrical appliances to fail, and other similar phenomena.

Electric charges flow from a large area through the substance of ball lightning and are dissipated in the atmosphere.

The explosion of ball lightning in many (it is possible that almost all) cases is a consequence of such a short-term electrical discharge.

Injuries to humans and animals by ball lightning also appear to be associated with the current pulses it produces.

The energy reserve of ball lightning can range from several kilojoules to several tens of kilojoules, in some cases (especially with large lightning sizes), perhaps up to a hundred kilojoules. Energy density 1-10 kJ. However, the effects of an explosion may be determined, at least in some cases, not by the energy of the ball lightning itself, but by the energy accumulated during a thunderstorm in charged conductors and the electric fields surrounding them. In this case, ball lightning plays the role of a trigger mechanism, including the process of releasing this energy.

The substance of ball lightning forms a separate phase in the air, which has significant surface energy. The existence of surface tension is indicated by the stability of the boundary of ball lightning, including when it moves in the surrounding air (sometimes in strong winds), the stability of the spherical shape and its restoration after deformations arising from interaction with surrounding bodies. It should be noted that the spherical shape of lightning is restored even after large deformations accompanied by the disintegration of ball lightning into parts.

In addition, surface waves are often observed on the surface of ball lightning. With a sufficiently large amplitude, these waves lead to the ejection of droplets of substance from the surface, similar to splashes of liquid.

The existence of non-spherical ball lightning (pear-shaped, elliptical) can be caused by polarization in strong magnetic fields.

Ball lightning can carry an electric charge, which appears, for example, during polarization in an electric field (especially if charges of different signs flow differently from its surface). The movement of ball lightning under conditions of indifferent equilibrium, in which the force of gravity is balanced by the Archimedean force, is determined by both electric fields and air movement.

There is a correlation between the lifetime and the size of lightning.

Long-lived lightning turns out to be mostly large in size (according to data, they account for 80% of lightning with a diameter of more than 30 cm and only 20% of lightning with a diameter of less than 10 cm). On the contrary, short-lived lightning has a small diameter (80% of lightning with a diameter of less than 10 cm and 20% with a diameter of more than 30 cm).

Analyzing observations, it can be assumed that ball lightning appears where a significant electrical charge accumulates, with a powerful but short-term emission of this charge into the air.

Ball lightning disappears as a result of an explosion, the development of instabilities, or due to the gradual consumption of its energy and matter reserves (quiet extinction). The nature of the ball lightning explosion is not entirely clear.

Most lightning - about 60% - emits visible light, which is at the red end of the spectrum (red, orange or yellow). About 15% emits light in the short-wave part of the spectrum (blue, less often blue, violet, green). Finally, in approximately 25% of cases the lightning is white.

The power of the emitted light is on the order of several watts. Since the temperature of lightning is low, its visible radiation is of a nonequilibrium nature. It is possible that lightning also emits some ultraviolet radiation, the absorption of which in the air could explain the blue halo around it.

Heat exchange between ball lightning and the environment occurs through the emission of a significant amount of infrared radiation. If a temperature of 500-600 K can indeed be attributed to ball lightning, then the power of the equilibrium thermal radiation emitted by lightning of average diameter (cm) is about 0.5-1 kW and the maximum radiation lies in the wavelength region of 5-10 microns.

In addition to infrared and visible radiation, ball lightning can emit quite strong nonequilibrium radio emission.

All hypotheses concerning the physical nature of ball lightning can be divided into two groups. One group includes hypotheses according to which ball lightning continuously receives energy from the outside. It is assumed that lightning somehow receives energy accumulating in clouds and clouds, and the heat release in the channel itself turns out to be insignificant, so that all the transmitted energy is concentrated in the volume of ball lightning, causing it to glow. Another group includes hypotheses according to which ball lightning becomes an independently existing object. This object consists of a certain substance within which processes occur that lead to the release of energy.

Among the hypotheses of the first group, we note the hypothesis proposed in 1965 by Academician Kapitsa. He calculated that ball lightning's own energy reserves should be enough for its existence within hundredths of a second. In nature, as is known, it exists much longer and often ends its existence with an explosion. The question arises, where does the energy come from?

The search for a solution led Kapitsa to the conclusion that “if there are no energy sources in nature that are still unknown to us, then, based on the law of conservation of energy, we have to accept that during the glow, energy is continuously supplied to the ball lightning, and we are forced to look for a source outside the volume of the ball lightning ". The academician theoretically showed that ball lightning is a high-temperature plasma that exists for quite a long time due to resonant absorption or intense energy supply in the form of radio wave radiation.

He suggested that artificial ball lightning could be created using a powerful stream of radio waves focused into a limited area of space (If the lightning is a ball with a diameter of about 35-70 cm.)

But despite the many attractive aspects of this hypothesis, it still seems untenable: it does not explain the nature of the movement of ball lightning, the dependence of its behavior on air currents; within the framework of this hypothesis, it is difficult to explain the clearly observed clear surface of lightning; the explosion of such ball lightning should not be accompanied by the release of energy and resembles a loud bang.

Several years ago, in one of the laboratories of the Research Institute of Mechanics of Moscow State University under the leadership of A.M. Hazen created another fireball theory.

According to it, during a thunderstorm, under the influence of a potential difference, a directed drift of electrons from the clouds to the ground begins. Along the way, the electrons, of course, collide with the gas molecules that make up the air, and, contrary to common sense, the higher the speed of the electron, the less frequently. As a result, individual atoms that have reached a certain critical speed roll down, as if down a hill. This “slide effect” rearranges the army of charged particles. They begin to roll in not in a disorderly crowd, but in ranks, just as the waves of the sea surf roll in. Only this “surf” has a colossal speed - 1000 km/s! The energy of such waves, as Hazen’s calculations show, is quite enough to, upon overtaking a plasma ball, feed it with its electrostatic field and maintain electromagnetic oscillations in it for some time. Hazen's theory answered some questions: why does ball lightning often move above the ground, as if copying the terrain? The explanation is as follows: on the one hand, the luminous sphere, having a higher temperature in relation to the environment, tends to float upward under the influence of Archimedean force; on the other hand, under the influence of electrostatic forces, the ball is attracted to the moist conductive surface of the soil. At some height, both forces balance each other and the ball seems to be rolling along invisible rails.

Sometimes, however, ball lightning makes sharp leaps. They can be caused by either a strong gust of wind or a change in the direction of movement of the electron avalanche.

An explanation was found for another fact: ball lightning tends to get inside buildings. Any structure, especially a stone one, raises the groundwater level in a given place, which means the electrical conductivity of the soil increases, which attracts the plasma ball.

And finally, why does ball lightning end its existence in different ways, sometimes silently, and more often with an explosion? Electronic drift is also to blame here. If too much energy is supplied to the spherical “vessel”, it will eventually burst from overheating or, once in an area of increased electrical conductivity, it will discharge, like ordinary linear lightning. If the electron drift fades for some reason, the ball lightning quietly fades away, dissipating its charge in the surrounding space.

A.M. Hazen created an interesting theory of one of the most mysterious phenomena of nature and proposed a scheme for its creation: “Let's take a conductor passing through the center of the antenna of a microwave transmitter. An electromagnetic wave will propagate along the conductor, as if along a waveguide. Moreover, the conductor must be taken long enough, so that the antenna does not electrostatically affect the free end. We connect this conductor to a high-voltage pulse generator and, turning on the generator, apply a short voltage pulse to it, sufficient for a corona discharge to occur at the free end. The pulse must be formed so that near it trailing edge, the voltage on the conductor did not drop to zero, but remained at some level, insufficient to create a corona, that is, a constantly glowing charge on the conductor. If you change the amplitude and time of the constant voltage pulse, vary the frequency and amplitude of the microwave field, then in the end ends at the free end of the wire, even after turning off the alternating field, a luminous plasma clot should remain and, possibly, separate from the conductor."

The need for a large amount of energy prevents the implementation of this experiment.

And yet, most scientists prefer the hypotheses of the second group.

One of them suggests the chemical nature of ball lightning. Dominic Arago was the first to suggest it. And in the mid-70s it was developed in detail by B.M. Smirnov. It is assumed that ball lightning consists of ordinary air (having a temperature approximately 100? higher than the temperature of the surrounding atmosphere), a small admixture of ozone and nitrogen oxides, etc. A fundamentally important role here is played by ozone, which is formed during the discharge of ordinary lightning; its concentration is about 3%.

A disadvantage of the physical model under consideration is also the impossibility of explaining the stable shape of ball lightning and the existence of surface tension.

In search of an answer, a new physical theory was developed. According to this hypothesis, ball lightning consists of positive and negative ions. Ions are formed due to the energy of the discharge of ordinary linear lightning. The energy spent on their formation determines the energy reserve of ball lightning. It is released when ions recombine. Due to the electrostatic (Coulomb) forces acting between the ions, the volume filled with ions will have surface tension, which determines the stable spherical shape of lightning.

Stakhanov, like many other physicists, proceeded from the fact that lightning consists of a substance in the state of plasma. Plasma is similar to a gaseous state with the only difference: the molecules of the substance in plasma are ionized, that is, they have lost (or vice versa acquired extra) electrons and are no longer neutral. This means that molecules can interact not only as gas particles - in collisions, but also at a distance using electrical forces.

Oppositely charged particles attract each other. Therefore, in plasma, molecules strive to regain their lost charge by recombining with detached electrons. But after recombination, the plasma will turn into ordinary gas. Plasma can be kept alive only as long as something interferes with recombination - usually a very high temperature.

If ball lightning is a plasma ball, then it must be hot. This is how supporters of plasma models argued before Stakhanov. And he noticed that there was another possibility. Ions, that is, molecules that have lost or captured an extra electron, can attract ordinary neutral water molecules and surround themselves with a strong “water” shell, locking the extra electrons inside and preventing them from reuniting with their owners. This is possible because a water molecule has two poles: negative and positive, one of which is “grabbed” by the ion, depending on its charge, in order to attract the molecule to itself. Thus, ultra-high temperatures are no longer needed, the plasma can remain “cold”, not hotter than 200-300 degrees. An ion surrounded by a water shell is called a cluster, which is why Professor Stakhanov’s hypothesis was named cluster.

The most important advantage of the cluster hypothesis is that it continues not only to live in science, but also to be enriched with new content. A group of researchers from the Institute of General Physics of the Russian Academy of Sciences, which includes Professor Sergei Yakovlenko, recently obtained striking new results.

It turned out that the water shell itself cannot be so dense as to prevent the ions from recombining. But recombination leads to an increase in the entropy of ball lightning, that is, the measure of its disorder. Indeed, in plasma, positively and negatively charged molecules differ from each other, interact in a special way, and after recombination they mix and become indistinguishable. Until now, it was believed that in a system left to its own devices, disorder increases spontaneously, that is, in the case of ball lightning, recombination will occur by itself if it is not somehow prevented. From the results of computer modeling and theoretical calculations carried out at the Institute of General Physics, a completely different conclusion follows: disorder is introduced into the system from the outside, for example, during chaotic collisions of molecules at the boundary of ball lightning and the air in which it moves. Until the disorder “accumulates,” recombination will not occur, even though the molecules tend to do so. The nature of their movement inside ball lightning is such that when approaching, oppositely charged molecules will fly past each other without having time to exchange charge.

So, according to the cluster hypothesis, ball lightning is an independently existing body (without a continuous supply of energy from external sources), consisting of heavy positive and negative ions, the recombination of which is greatly inhibited due to ion hydration.

Unlike many other hypotheses, this one can withstand comparison with the results of several thousand currently known observations and satisfactorily explains many of them.

In 2000, the journal Nature presented the work of New Zealand chemists John Abrahamson and James Dinnis. They showed that when lightning strikes soil containing silicates and organic carbon, a tangle of silicon and silicon carbide fibers is formed. These fibers slowly oxidize and begin to glow - a fireball, heated to 1200-1400°C, breaks out. Usually ball lightning melts silently, but sometimes it explodes. According to Abrahamson and Dinnis, this happens if the initial temperature of the ball is too high. Then the oxidative processes proceed at an accelerated rate, which leads to an explosion. However, this hypothesis cannot describe all cases of observation of ball lightning.

In 2004, Russian researchers A.I. Egorov, S.I. Stepanov and G.D. Shabanov described an installation diagram in which they were able to obtain ball discharges, which they called “plasmoids” and resembled ball lightning. The experiments were quite possible to reproduce, but the plasmoids existed for no more than a second.

In February 2006, a message came from Tel Aviv University. Physicists Vladimir Dikhtyar and Eli Yerby observed glowing balls of gas in the laboratory, much like those strange lightning bolts. To generate them, Dikhtyar and Yerby heated the silicon substrate in a 600-watt microwave field until it evaporated. A yellowish-red ball with a diameter of about 3 centimeters, consisting of ionized gas (as you can see, noticeably smaller than ball lightning) appeared in the air. It floated slowly in the air, maintaining its shape until the installation that created the field was turned off. The surface temperature of the ball reached 1700°C. Like ordinary lightning, it was attracted to metal objects and slid along them, but could not penetrate the window glass. In the experiments of Dikhtyar and Yerby, glass burst when it came into contact with a fireball.

Obviously, in nature, ball lightning is generated not by microwave fields, but by electrical discharges. In any case, Israeli scientists have demonstrated that the study of such lightning is permissible in laboratory conditions and that the results of the experiments can be used to create new technologies for processing materials, in particular, for depositing ultra-thin films.

The number of different hypotheses about the nature of ball lightning significantly exceeds a hundred, but we have examined only a few. None of the currently existing hypotheses is perfect; each has many shortcomings.

Therefore, although the fundamental laws of the nature of ball lightning are understood, this problem cannot be considered solved - many secrets and mysteries remain, and there are no specific ways to create it in laboratory conditions.

This discharge is characterized by an intermittent form (even when using direct current sources). It usually occurs in gases at pressures on the order of atmospheric pressure. Under natural conditions, a spark discharge is observed in the form of lightning. Externally, a spark discharge is a bunch of bright zigzag branching thin strips that instantly penetrate the discharge gap, quickly extinguish and constantly replace each other (Fig. 5). These strips are called spark channels. They start from both positive and negative, and from any point in between. The channels developing from the positive electrode have clear thread-like outlines, while those developing from the negative electrode have diffuse edges and finer branching.

Because Since a spark discharge occurs at high gas pressures, the ignition potential is very high. (For dry air, for example, at a pressure of 1 atm. and a distance between the electrodes of 10 mm, the breakdown voltage is 30 kV.) But after the discharge gap becomes a “spark” channel, the resistance of the gap becomes very small, a short-term pulse of high current passes through the channel , during which there is only a small amount of resistance per discharge gap. If the source power is not very high, then after such a current pulse the discharge stops. The voltage between the electrodes begins to rise to its previous value, and the gas breakdown is repeated with the formation of a new spark channel.

The value of Ek increases with increasing pressure. The ratio of the critical field strength to the gas pressure p for a given gas remains approximate over a wide range of pressure changes: Ek/pconst.

The greater the capacitance C between the electrodes, the longer the voltage rise time. Therefore, turning on a capacitor parallel to the discharge gap increases the time between two subsequent sparks, and the sparks themselves become more powerful. A large electric charge passes through the spark channel, and therefore the amplitude and duration of the current pulse increases. With a large capacitance C, the spark channel glows brightly and has the appearance of wide stripes. The same thing happens when the power of the current source increases. Then they talk about a condensed spark discharge, or a condensed spark. The maximum current strength in a pulse during a spark discharge varies widely, depending on the parameters of the discharge circuit and the conditions in the discharge gap, reaching several hundred kiloamperes. With a further increase in source power, the spark discharge turns into an arc discharge.

As a result of the passage of a current pulse through the spark channel, a large amount of energy is released in the channel (about 0.1 - 1 J for each centimeter of channel length). The release of energy is associated with an abrupt increase in pressure in the surrounding gas - the formation of a cylindrical shock wave, the temperature at the front of which is ~104 K. A rapid expansion of the spark channel occurs, with a speed on the order of the thermal speed of gas atoms. As the shock wave advances, the temperature at its front begins to drop, and the front itself moves away from the channel boundary. The occurrence of shock waves is explained by the sound effects that accompany a spark discharge: a characteristic crackling sound in weak discharges and powerful rumbles in the case of lightning.

When the channel exists, especially at high pressures, a brighter glow of the spark discharge is observed. The brightness of the glow is nonuniform over the cross section of the channel and has a maximum in its center.

Let's consider the spark discharge mechanism.

Currently, the so-called streamer theory of spark discharge, confirmed by direct experiments, is generally accepted. Qualitatively, it explains the main features of a spark discharge, although quantitatively it cannot be considered complete. If an electron avalanche originates near the cathode, then along its path there is ionization and excitation of gas molecules and atoms. It is important that light quanta emitted by excited atoms and molecules, propagating to the anode at the speed of light, themselves produce ionization of the gas and give rise to the first electron avalanches. In this way, weakly glowing accumulations of ionized gas, called streamers, appear throughout the entire volume of gas. In the process of their development, individual electron avalanches catch up with each other and, merging together, form a well-conducting bridge of streamers. Therefore, at the next moment in time, a powerful flow of electrons rushes, forming a spark discharge channel. Since the conducting bridge is formed as a result of the merger of streamers that appear almost simultaneously, the time of its formation is much less than the time required for an individual electron avalanche to travel the distance from the cathode to the anode. Along with negative streamers, i.e. streamers propagating from the cathode to the anode, there are also positive streamers that propagate in the opposite direction.

Free electrons receive enormous accelerations in such a field. These accelerations are directed downward, since the lower part of the cloud is negatively charged, and the surface of the earth is positively charged. On the way from the first collision to the next, the electrons acquire significant kinetic energy. Therefore, when they collide with atoms or molecules, they ionize them. As a result, new (secondary) electrons are born, which, in turn, are accelerated in the field of the cloud and then ionize new atoms and molecules in collisions. Whole avalanches of fast electrons arise, forming clouds at the very “bottom”, plasma “threads” - a streamer.

Merging with each other, the streamers give rise to a plasma channel through which the main current pulse will subsequently pass. This plasma channel developing from the “bottom” of the cloud to the surface of the earth is filled with free electrons and ions, and therefore can conduct electric current well. He is called a leader, or more precisely a stepped leader. The fact is that the channel is not formed smoothly, but in jumps - in “steps”.

Why there are pauses in the leader’s movement, and relatively regular ones at that, is not known for sure. There are several theories of stepped leaders.

In 1938, Schonland put forward two possible explanations for the delay that causes the step-like nature of the leader. According to one of them, electrons should move down the channel of the leading streamer (pilot). However, some electrons are captured by atoms and positively charged ions, so that it takes some time for new advancing electrons to arrive before there is a potential gradient sufficient for the current to continue. According to another point of view, time is required for positively charged ions to accumulate under the head of the leader channel and, thus, create a sufficient potential gradient across it. In 1944, Bruce proposed a different explanation, which was based on the development of a glow discharge into an arc discharge. He considered a "corona discharge", similar to a tip discharge, existing around the leader channel, not only at the head of the channel, but along its entire length. He explained that the conditions for the existence of an arc discharge will be established for some time after the channel has developed over a certain distance and, therefore, steps have arisen. This phenomenon has not yet been fully studied and there is no specific theory yet. But the physical processes occurring near the leader’s head are quite understandable. The field strength under the cloud is quite high - it is B/m; in the area of space directly in front of the leader's head it is even greater. The increase in field strength in this region is well explained by Fig. 4, where the dashed curves show sections of equipotential surfaces, and the solid curves show the field strength lines. In a strong electric field near the leader head, intense ionization of atoms and air molecules occurs. It occurs due to, firstly, the bombardment of atoms and molecules by fast electrons emitted from the leader (the so-called impact ionization), and, secondly, the absorption of photons of ultraviolet radiation emitted by the leader by atoms and molecules (photoionization). Due to the intense ionization of atoms and air molecules encountered on the path of the leader, the plasma channel grows, the leader moves towards the surface of the earth.

The second stage proceeds quickly and powerfully. The main current flows along the path laid by the leader. The current pulse lasts approximately 0.1 ms. The current strength reaches values of the order of A. A significant amount of energy is released (up to J). The gas temperature in the channel reaches. It is at this moment that the unusually bright light that we observe during a lightning discharge is born, and thunder occurs, caused by the sudden expansion of the suddenly heated gas.

It is important that both the glow and the heating of the plasma channel develop in the direction from the ground to the cloud, i.e. down up. To explain this phenomenon, let us conditionally divide the entire channel into several parts. As soon as the channel has formed (the leader's head has reached the ground), first of all the electrons that were in its lowest part jump down; therefore, the lower part of the channel first begins to glow and warm up. Then electrons from the next (higher part of the channel) rush to the ground; the glow and heating of this part begin. And so gradually - from bottom to top - more and more electrons are included in the movement towards the ground; As a result, the glow and heating of the channel propagate in the direction from bottom to top.

After the main current pulse has passed, there is a pause lasting from 10 to 50 ms. During this time, the channel practically goes out, its temperature drops, and the degree of ionization of the channel decreases significantly.

However, a large charge is still retained in the cloud, so the new leader rushes from the cloud to the ground, preparing the way for a new current pulse. The leaders of the second and subsequent strikes are not stepped, but arrow-shaped. Arrowhead leaders are similar to the steps of a stepped leader. However, since the ionized channel already exists, the need for a pilot and stages is eliminated. Since the ionization in the channel of the swept leader is “older” than that of the stepped leader, recombination and diffusion of charge carriers occurs more intensely, and therefore the degree of ionization in the channel of the swept leader is lower. As a result, the speed of the swept leader is less than the speed of the individual stages of the stepped leader, but greater than the speed of the pilot. The speed values of the swept leader range from to m/s.

If more time than usual elapses between subsequent lightning strikes, the degree of ionization may be so low, especially in the lower part of the channel, that a new pilot becomes necessary to re-ionize the air. This explains individual cases of the formation of steps at the lower ends of the leaders, preceding not the first, but the subsequent main lightning strikes.

As stated above, the new leader follows the path that was blazed by the original leader. It runs all the way from top to bottom without stopping (1ms). And again a powerful pulse of the main current follows. After another pause, everything repeats. As a result, several powerful impulses are emitted, which we naturally perceive as a single lightning discharge, as a single bright flash.

Before the invention of electricity and lightning rods, people fought the destructive effects of lightning strikes with spells. In Europe, continuous ringing of bells during a thunderstorm was considered an effective means of fighting. According to statistics, the result of a 30-year fight against lightning in Germany was the destruction of 400 bell towers and the death of 150 bell ringers.

The first person to come up with an effective method was the US scientist Benjamin Franklin, a universal genius of his era (1706-1790).

How Franklin deflected lightning. Fortunately, most lightning strikes occur between clouds and therefore pose no threat. However, it is believed that lightning kills more than a thousand people around the world every year. At least in the United States, where such statistics are kept, about 1,000 people suffer from lightning strikes every year and more than a hundred of them die. Scientists have long tried to protect people from this “punishment of God.” For example, the inventor of the first electric capacitor (Leyden jar), Pieter van Muschenbrouck (1692-1761), in an article on electricity written for the famous French Encyclopedia, defended traditional methods of preventing lightning - ringing bells and firing cannons, which he believed were quite effective. effective.

Benjamin Franklin, trying to protect the Capitol of the capital of the state of Maryland, in 1775 attached a thick iron rod to the building, which rose several meters above the dome and was connected to the ground. The scientist refused to patent his invention, wanting it to begin serving people as soon as possible (Fig. 6).

The news of Franklin's lightning rod quickly spread throughout Europe, and he was elected to all academies, including the Russian one. However, in some countries the devout population greeted this invention with indignation. The very idea that a person could so easily and simply tame the main weapon of “God’s wrath” seemed blasphemous. Therefore, in different places people, for pious reasons, broke lightning rods. A curious incident occurred in 1780 in the small town of Saint-Omer in northern France, where the townspeople demanded that the iron lightning rod mast be demolished, and the matter came to trial. The young lawyer, who defended the lightning rod from the attacks of obscurantists, based his defense on the fact that both the human mind and his ability to conquer the forces of nature are of divine origin. Everything that helps save a life is for the good, the young lawyer argued. He won the case and gained great fame. The lawyer's name was Maximilian Robespierre. Well, now the portrait of the inventor of the lightning rod is the most desirable reproduction in the world, because it adorns the well-known hundred dollar bill.

How to protect yourself from lightning using a water jet and a laser. Recently, a fundamentally new method of combating lightning was proposed. A lightning rod will be created from... a jet of liquid that will be shot from the ground directly into thunderclouds. Lightning liquid is a saline solution to which liquid polymers are added: the salt is intended to increase electrical conductivity, and the polymer prevents the jet from “breaking up” into individual droplets. The diameter of the jet will be about a centimeter, and the maximum height will be 300 meters. When the liquid lightning rod is finalized, it will be equipped with sports and children's playgrounds, where the fountain will turn on automatically when the electric field strength becomes high enough and the probability of a lightning strike is maximum. A charge will flow down a stream of liquid from a thundercloud, making lightning safe for others. Similar protection against lightning discharge can be done using a laser, the beam of which, ionizing the air, will create a channel for an electrical discharge away from crowds of people.

Can lightning lead us astray? Yes, if you use a compass. In the famous novel by G. Melville "Moby Dick" exactly such a case is described when a lightning discharge, which created a strong magnetic field, remagnetized the compass needle. However, the captain of the ship took a sewing needle, hit it to magnetize it, and replaced it with the damaged compass needle.

Can you be struck by lightning inside a house or airplane? Unfortunately yes! Lightning current can enter a house through a telephone wire from a nearby pole. Therefore, during a thunderstorm, try not to use a regular phone. It is believed that talking on a radiotelephone or mobile phone is safer. During a thunderstorm, you should not touch the central heating and water pipes that connect the house to the ground. For the same reasons, experts advise turning off all electrical appliances during a thunderstorm, including computers and televisions.

As for airplanes, generally speaking, they try to fly around areas with thunderstorm activity. And yet, on average, one of the planes is struck by lightning once a year. Its current cannot affect passengers; it flows down the outer surface of the aircraft, but it can damage radio communications, navigation equipment and electronics.

Doctors believe that a person who survives a lightning strike (and there are many such people), even without receiving severe burns to the head and body, may subsequently suffer complications in the form of deviations in cardiovascular and neuralgic activity from the norm. However, it may work out.

People realized a long time ago what harm a lightning strike could cause, and they came up with protection against it. But again, for some reason they called it a lightning rod, although it “diverts” not thunder, but lightning. A lightning rod is an iron pole that is placed as high as possible. After all, lightning must first make a path for itself in the air. It is clear that the shorter the track, the easier it is to make. And lightning is a terrible lazy person, always looking for the shortest path and striking the highest (and, therefore, closest to it) object. When lightning “sees” a tall iron pole nearby, prepared for it by people, it makes a path towards it. And the lightning rod is connected to the ground by a wire, and all the lightning electricity, without causing harm to anyone, goes into the ground. But before, a long time ago, there were large fires in cities and villages from lightning strikes.

Rabbi Yehuda Nachshoni cites a commentary by Rabbi Bachya (died 1340), who believed that the Tower of Babel was supposed to be a kind of lightning rod against the lightning with which the Almighty intended to burn the earth. The encyclopedia says that the lightning rod was invented by Benjamin Franklin (1706-1790) in America. We don’t argue that he was really interested in this issue, managed to use the accumulated experience and give practical application to his ideas. However, as we see, even at the time of compilation of the Mishnah (1500 years earlier), lightning rods were already in use. Therefore, it can be considered that the primacy attributed to Franklin is in fact rather dubious. Memories of things that have become familiar to us go into the distant past, and it is not always possible to find the one who was the first to discover for us something without which we can no longer imagine our lives.

Conclusion

Lightning is one of the most destructive and terrifying natural phenomena that humans encounter everywhere.

At the moment, the modern level of science and technology makes it possible to create a truly functionally reliable lightning protection system that meets the technical level.

About 32 billion lightning strikes occur on Earth per year, causing damage estimated at $5 billion. In the United States alone, about 1,000 people suffer from lightning every year, two hundred of whom die.

According to statistics, lightning strikes airplanes on average three times a year, but these days it rarely leads to serious consequences. Modern airliners are now fairly well protected from lightning strikes. The worst aviation accident caused by lightning occurred on December 8, 1963 in Maryland, USA. Then the lightning that struck the plane penetrated the reserve fuel tank, which led to the ignition of the entire plane. As a result, 82 people died.

Ball lightning is a mysterious natural phenomenon, observations of which have been reported for several centuries. Great progress in the study of this phenomenon has been achieved in the last ten to fifteen years. The study of the mysterious phenomenon is progressing due to the development of related fields of physics and chemistry.

It is natural to assume that the nature of ball lightning is based on known physical laws, but their combination leads to a new quality that we do not understand. Having understood this, we will find real what previously seemed exotic, and we will obtain qualitative ideas that may have analogues in other physical processes and phenomena. Gaining such insights enriches science and is valuable in the research at hand. This is the logic of the development of science in general, and the accumulated experience in studying the nature of ball lightning confirms this.

In the course of writing the abstract, special literature was studied, thanks to which the purpose of this abstract was fulfilled: the causes of lightning were considered, various types of electrical charges were studied, and various types of protection were considered.

1. Bogdanov, K.Yu. Lightning: more questions than answers // Science and life. – 2007. - No. 2. – P. 19-32.

2. Demkin, S. A bright personality with a dark past // Miracles and adventures. – 2007. - No. 4. – P. 44-45.

3. Imyanitov, I.M., Chubarina, E.V., Shvarts Ya.M. Electricity of the clouds. L., 197. – 593 p.

4. Ostapenko, V. Ball lightning - a clot of cold plasma // Youth technology. – 2007. - No. 884. – P. 16-19.

5.Peryshkin, A.V., Gutnik, E.M. Physics. 9th grade Textbook for general education institutions. - M.: Bustard, 2003. – 256 p.

6. Tarasov, L.V. Physics in nature. - M.: Education, 1988. – 352 p.

7. Frenkel, Ya.I. Collection of selected works, vol. 2.: M. -L., 1958. – 600 p.

Have you ever wondered why birds sit on high-voltage wires, and a person dies when he touches the wires? Everything is very simple - they sit on a wire, but no current flows through the bird, but if the bird flaps its wing, simultaneously touching two phases, it will die. Usually large birds such as storks, eagles, and falcons die this way.

Likewise, a person can touch a phase and nothing will happen to him if no current flows through him; for this you need to wear rubberized boots and God forbid you touch a wall or metal.

Electric current can kill a person in a split second; it strikes without warning. Lightning strikes the earth one hundred times per second and over eight million times per day. This force of nature is five times hotter than the surface of the sun. The electrical discharge strikes with a force of 300,000 amperes and a million volts in a split second. In our daily lives, we think we can control the electricity that powers our homes, outdoor lights, and now our cars. But electricity in its original form cannot be controlled. And lightning is electricity on a huge scale. And yet lightning remains a big mystery. It can strike unexpectedly and its path can be unpredictable.

Lightning in the sky does no harm, but one in ten lightning strikes the surface of the earth. Lightning is divided into many branches, each of which is capable of striking a person located at the epicenter. When a person is struck by lightning, the current can pass from one person to another if they come into contact.

There is a rule of thirty and thirty: if you see lightning and hear thunder less than thirty seconds later, you must seek shelter, and then you must wait thirty minutes from the last clap of thunder before going outside. But lightning does not always obey a strict order.

There is such an atmospheric phenomenon as thunder from a clear sky. Often lightning, leaving a cloud, travels up to sixteen kilometers before striking the ground. In other words, lightning can appear out of nowhere. Lightning needs wind and water. When strong winds lift moist air, the conditions are created for destructive thunderstorms to occur.

It is impossible to decompose into components something that fits into a millionth of a second. One false belief is that we see lightning as it travels to the ground, but what we actually see is the lightning's return path into the sky. Lightning is not a unidirectional strike to the ground, but is actually a ring, a path in two directions. The flash of lightning that we see is the so-called return stroke, the final phase of the cycle. And when the return stroke of lightning heats up the air, its calling card appears - thunder. The return path of lightning is the part of lightning that we see as a flash and hear as thunder. A reverse current of thousands of amperes and millions of volts rushes from the ground to the cloud.

Lightning regularly electrocutes people indoors. It can enter a structure in different ways, through drainpipes and water pipes. Lightning can penetrate electrical wiring, the current strength of which in an ordinary house does not reach two hundred amperes and overloads the electrical wiring in jumps from twenty thousand to two hundred thousand amperes. Perhaps the most dangerous path in your home leads directly to your hand through the phone. Nearly two-thirds of indoor electric shocks occur when people pick up a landline telephone during a lightning strike. Cordless phones are safer during thunderstorms, but lightning can electrocute someone standing near the phone's base. Even a lightning rod cannot protect you from all lightning, since it is not capable of catching lightning in the sky.

About the nature of lightning

There are several different theories explaining the origin of lightning.

Typically, the bottom of the cloud carries a negative charge and the top carries a positive charge, making the cloud-ground system like a giant capacitor.

When the electrical potential difference becomes large enough, a discharge known as lightning occurs between the ground and the cloud, or between two parts of the cloud.

Is it dangerous to be in a car during lightning?

In one of these experiments, a meter-long artificial lethal lightning was aimed at the steel roof of a car in which a person was sitting. Lightning passed through the casing without harming a person. How did this happen? Since charges on a charged object repel each other, they tend to move as far apart as possible.

In the case of a hollow mechanical ball pi cylinder, the charges are distributed over the outer surface of the object. Similarly, if lightning strikes the metal roof of a car, then the repelling electrons will spread extremely quickly over the surface of the car and go through its body into the ground. Therefore, lightning along the surface of a metal car goes into the ground and does not get inside the car. For the same reason, a metal cage is perfect protection against lightning. As a result of artificial lightning striking a car with a voltage of 3 million volts, the potential of the car and the body of the person in it increases to almost 200 thousand volts. At the same time, a person does not experience the slightest sign of an electric shock, since there is no potential difference between any points of his body.

This means that staying in a well-grounded building with a metal frame, of which there are many in modern cities, almost completely protects against lightning.

How can we explain that birds sit on the wires completely calmly and with impunity?

The body of a sitting bird is like a branch of a chain (parallel connection). The resistance of this branch with the bird is much greater than the resistance of the wire between the bird's legs. Therefore, the current strength in the bird’s body is negligible. If a bird, sitting on a wire, touched the pole with its wing or tail, or otherwise connected with the ground, it would be instantly killed by the current that would rush through it into the ground.

Interesting facts about lightning

The average length of lightning is 2.5 km. Some discharges extend up to 20 km in the atmosphere.

Lightning is beneficial: they manage to snatch millions of tons of nitrogen from the air, bind it and send it into the ground, fertilizing the soil.

Saturn's lightning is a million times stronger than Earth's.

A lightning discharge usually consists of three or more repeated discharges - pulses following the same path. The intervals between successive pulses are very short, from 1/100 to 1/10 s (this is what causes lightning to flicker).

About 700 lightning flashes on Earth every second. World centers of thunderstorms: the island of Java - 220, equatorial Africa - 150, southern Mexico - 142, Panama - 132, central Brazil - 106 thunderstorm days a year. Russia: Murmansk - 5, Arkhangelsk - 10, St. Petersburg - 15, Moscow - 20 thunderstorm days a year.

The air in the zone of the lightning channel almost instantly heats up to a temperature of 30,000-33,000 ° C. On average, about 3,000 people die from lightning strikes in the world every year

Statistics show that every 5,000-10,000 flight hours there is one lightning strike on an aircraft; fortunately, almost all damaged aircraft continue to fly.

Despite the crushing power of lightning, protecting yourself from it is quite simple. During a thunderstorm, you should immediately leave open areas, under no circumstances should you hide under isolated trees, or be near high masts and power lines. You should not hold steel objects in your hands. Also, during thunderstorms, you cannot use radio communications or mobile phones. Televisions, radios and electrical appliances must be turned off indoors.

Lightning rods protect buildings from lightning damage for two reasons: they allow the charge induced on the building to flow into the air, and when lightning strikes the building, they take it into the ground.

If you find yourself in a thunderstorm, you should avoid taking shelter near single trees, hedges, elevated places and being in open spaces.

Even 250 years ago, the famous American scientist and public figure Benjamin Franklin established that lightning is an electrical discharge. But it has still not been possible to fully reveal all the secrets that lightning holds: studying this natural phenomenon is difficult and dangerous.

(20 photos of lightning + video Lightning in slow motion)

Inside the clouds

A thundercloud cannot be confused with an ordinary cloud. Its gloomy, leaden color is explained by its great thickness: the lower edge of such a cloud hangs at a distance of no more than a kilometer above the ground, while the upper edge can reach a height of 6-7 kilometers.

What's going on inside this cloud? The water vapor that makes up clouds freezes and exists in the form of ice crystals. Rising air currents coming from the heated earth carry small pieces of ice upward, forcing them to constantly collide with large ones that settle down.

By the way, in winter the earth heats up less, and at this time of year, practically no powerful upward flows are formed. Therefore, winter thunderstorms are an extremely rare occurrence.

During collisions, the pieces of ice become electrified, just as happens when various objects rub against one another, for example, a comb on hair. Moreover, small pieces of ice acquire a positive charge, and large ones - a negative one. For this reason, the upper part of the lightning-forming cloud acquires a positive charge, and the lower part acquires a negative charge. A potential difference of hundreds of thousands of volts arises at every meter of distance - both between the cloud and the ground, and between parts of the cloud.

Development of lightning

The development of lightning begins with the fact that in some place in the cloud a center appears with an increased concentration of ions - water molecules and gases that make up the air, from which electrons have been taken away or to which electrons have been added.

According to one hypothesis, such an ionization center is obtained due to the acceleration in the electric field of free electrons, always present in the air in small quantities, and their collision with neutral molecules, which are immediately ionized.

According to another hypothesis, the initial shock is caused by cosmic rays, which constantly penetrate our atmosphere, ionizing air molecules.

Ionized gas is a good conductor of electricity, so current begins to flow through the ionized areas. Further - more: the passing current heats the ionization area, causing more and more high-energy particles that ionize nearby areas - the lightning channel spreads very quickly.

Following the leader

In practice, the process of lightning development occurs in several stages. First, the leading edge of the conducting channel, called the “leader,” moves in leaps of several tens of meters, each time changing direction slightly (this makes the lightning appear tortuous). Moreover, the speed of advancement of the “leader” can, at some moments, reach 50 thousand kilometers in one single second.

Eventually, the “leader” reaches the ground or another part of the cloud, but this is not yet the main stage of the further development of lightning. After the ionized channel, the thickness of which can reach several centimeters, is “broken,” charged particles rush through it at enormous speed—up to 100 thousand kilometers in just one second—this is lightning itself.

The current in the channel is hundreds and thousands of amperes, and the temperature inside the channel, at the same time, reaches 25 thousand degrees - that is why lightning gives such a bright flash, visible for tens of kilometers. And instantaneous temperature changes of thousands of degrees create enormous differences in air pressure, spreading in the form of a sound wave—thunder. This stage lasts very briefly - thousandths of a second, but the energy that is released is enormous.

Final stage

At the final stage, the speed and intensity of charge movement in the channel decreases, but still remains quite large. It is this moment that is most dangerous: the final stage can last only tenths (or even less) of a second. Such a fairly long-term impact on objects on the ground (for example, dry trees) often leads to fires and destruction.

Moreover, as a rule, the matter is not limited to one discharge - new “leaders” can move along the beaten path, causing repeated discharges in the same place, the number reaching several dozen.

Despite the fact that lightning has been known to mankind since the appearance of man himself on Earth, to this day it has not yet been fully studied.

Lightning 1882
(c) Photographer: William N. Jennings, c. 1882

The electrical nature of lightning was revealed in the research of the American physicist B. Franklin, on whose idea an experiment was carried out to extract electricity from a thundercloud. Franklin's experience in elucidating the electrical nature of lightning is widely known. In 1750, he published a work that described an experiment using a kite launched into a thunderstorm. Franklin's experience was described in the work of Joseph Priestley.

Physical properties of lightning

The average length of lightning is 2.5 km, some discharges extend up to 20 km in the atmosphere.

Lightning Formation

Most often, lightning occurs in cumulonimbus clouds, then they are called thunderstorms; Lightning sometimes forms in nimbostratus clouds, as well as during volcanic eruptions, tornadoes and dust storms.

Typically observed are linear lightning, which belongs to the so-called electrodeless discharges, since they begin (and end) in accumulations of charged particles. This determines their some still unexplained properties that distinguish lightning from discharges between electrodes. Thus, lightning does not occur shorter than several hundred meters; they arise in electric fields much weaker than the fields during interelectrode discharges; The collection of charges carried by lightning occurs in thousandths of a second from billions of small particles, well isolated from each other, located in a volume of several km³. The most studied process of lightning development in thunderclouds, while lightning can occur in the clouds themselves - intracloud lightning, or they can hit the ground - ground lightning. For lightning to occur, it is necessary that in a relatively small (but not less than a certain critical) volume of the cloud an electric field (see atmospheric electricity) with a strength sufficient to initiate an electrical discharge (~ 1 MV/m) must be formed, and in a significant part of the cloud there would be field with an average strength sufficient to maintain the started discharge (~ 0.1-0.2 MV/m). In lightning, the electrical energy of the cloud is converted into heat, light and sound.

Ground lightning

The development process of ground lightning consists of several stages. At the first stage, in the zone where the electric field reaches a critical value, impact ionization begins, created initially by free charges, always present in small quantities in the air, which, under the influence of the electric field, acquire significant speeds towards the ground and, colliding with the molecules that make up air, ionize them.

According to more modern concepts, ionization of the atmosphere for the passage of a discharge occurs under the influence of high-energy cosmic radiation - particles with energies of 10 12 -10 15 eV, forming a wide air shower (EAS) with a decrease in the breakdown voltage of the air by an order of magnitude from that under normal conditions.

According to one hypothesis, the particles trigger a process called runaway breakdown. Thus, electron avalanches arise, turning into threads of electrical discharges - streamers, which are highly conductive channels that, merging, give rise to a bright thermally ionized channel with high conductivity - stepped lightning leader.

The movement of the leader to the earth's surface occurs steps several tens of meters at a speed of ~ 50,000 kilometers per second, after which its movement stops for several tens of microseconds, and the glow greatly weakens; then, in the subsequent stage, the leader again advances several tens of meters. A bright glow covers all the steps passed; then a stop and weakening of the glow follows again. These processes are repeated as the leader moves to the surface of the earth at an average speed of 200,000 meters per second.

As the leader moves toward the ground, the field strength at its end increases and, under its action, objects are thrown out from objects protruding on the surface of the Earth. response streamer connecting to the leader. This feature of lightning is used to create a lightning conductor.

In the final stage, the channel ionized by the leader follows back(from bottom to top), or main, lightning discharge, characterized by currents from tens to hundreds of thousands of amperes, brightness, noticeably exceeding the brightness of the leader, and a high speed of advancement, initially reaching up to ~ 100,000 kilometers per second, and at the end decreasing to ~ 10,000 kilometers per second. The channel temperature during the main discharge can exceed 2000-3000 °C. The length of the lightning channel can be from 1 to 10 km, the diameter can be several centimeters. After the passage of the current pulse, the ionization of the channel and its glow weaken. In the final stage, the lightning current can last hundredths and even tenths of a second, reaching hundreds and thousands of amperes. Such lightning is called prolonged lightning and most often causes fires. But the ground is not charged, so it is generally accepted that a lightning discharge occurs from the cloud towards the ground (from top to bottom).

The main discharge often discharges only part of the cloud. Charges located at high altitudes can give rise to a new (swept) leader moving continuously at speeds of thousands of kilometers per second. The brightness of its glow is close to the brightness of the stepped leader. When the swept leader reaches the surface of the earth, a second main blow follows, similar to the first. Typically, lightning includes several repeated discharges, but their number can reach several dozen. The duration of multiple lightning can exceed 1 second. The displacement of the channel of multiple lightning by the wind creates the so-called ribbon lightning - a luminous strip.

Intracloud lightning

Intracloud lightning over Toulouse, France. 2006

Intracloud lightning usually includes only leader stages; their length ranges from 1 to 150 km. The proportion of intracloud lightning increases as it moves toward the equator, changing from 0.5 in temperate latitudes to 0.9 in the equatorial zone. The passage of lightning is accompanied by changes in electric and magnetic fields and radio emission, the so-called atmospherics.

Flight from Kolkata to Mumbai.

The probability of a ground object being struck by lightning increases as its height increases and with an increase in the electrical conductivity of the soil on the surface or at some depth (the action of a lightning rod is based on these factors). If there is an electric field in the cloud that is sufficient to maintain a discharge, but not sufficient to cause it to occur, a long metal cable or an airplane can act as the lightning initiator - especially if it is highly electrically charged. In this way, lightning is sometimes “provoked” in nimbostratus and powerful cumulus clouds.

Lightning in the upper atmosphere

In 1989, a special type of lightning was discovered - elves, lightning in the upper atmosphere. In 1995, another type of lightning in the upper atmosphere was discovered - jets.

Elves

Jets

Jets They are blue cone tubes. The height of the jets can reach 40-70 km (the lower limit of the ionosphere), jets live relatively longer than elves.

Sprites

Sprites are difficult to distinguish, but they appear in almost any thunderstorm at an altitude of 55 to 130 kilometers (the altitude of formation of “ordinary” lightning is no more than 16 kilometers). This is a kind of lightning striking upward from a cloud. This phenomenon was first recorded in 1989 by accident. Currently, very little is known about the physical nature of sprites.

Interaction of lightning with the surface of the earth and objects located on it

Global lightning strike frequency (scale shows number of strikes per year per square kilometer)

Early estimates put the frequency of lightning strikes on Earth at 100 times per second. Current data from satellites, which can detect lightning in areas where there is no ground observation, puts the frequency at an average of 44 ± 5 times per second, which equates to approximately 1.4 billion lightning strikes per year. 75% of this lightning strikes between or within clouds, and 25% strikes the ground.

The most powerful lightning strikes cause the birth of fulgurites.

Shock wave from lightning

A lightning discharge is an electrical explosion and is similar in some aspects to detonation. It causes a shock wave that is dangerous in the immediate vicinity. A shock wave from a sufficiently powerful lightning discharge at distances of up to several meters can cause destruction, break trees, injure and concuss people even without direct electric shock. For example, with a current rise rate of 30 thousand amperes per 0.1 millisecond and a channel diameter of 10 cm, the following shock wave pressures can be observed:

at a distance from the center of 5 cm (border of the luminous lightning channel) - 0.93 MPa,
at a distance of 0.5 m - 0.025 MPa (destruction of fragile building structures and human injuries),
at a distance of 5 m - 0.002 MPa (breaking glass and temporarily stunning a person).

At greater distances, the shock wave degenerates into a sound wave - thunder.

People and lightning

Lightning is a serious threat to human life. The defeat of a person or animal by lightning often occurs in open spaces, since the electric current travels along the shortest path “thundercloud-ground”. Often lightning strikes trees and transformer installations on the railway, causing them to catch fire. It is impossible to be struck by ordinary linear lightning inside a building, but there is an opinion that so-called ball lightning can penetrate through cracks and open windows. Normal lightning is dangerous for television and radio antennas located on the roofs of high-rise buildings, as well as for network equipment.

The same pathological changes are observed in the body of victims as in case of electric shock. The victim loses consciousness, falls, convulsions may occur, and breathing and heartbeat often stop. It is common to find “current marks” on the body, where electricity enters and exits. In case of death, the cause of cessation of basic vital functions is a sudden stop of breathing and heartbeat, from the direct effect of lightning on the respiratory and vasomotor centers of the medulla oblongata. So-called lightning marks, tree-like light pink or red stripes often remain on the skin, disappearing when pressed with fingers (they persist for 1 - 2 days after death). They are the result of the expansion of capillaries in the area of lightning contact with the body.

Lightning travels in a tree trunk along the path of least electrical resistance, releasing a large amount of heat, turning water into steam, which splits the tree trunk or, more often, tears off sections of bark from it, showing the lightning path. In subsequent seasons, the trees usually repair the damaged tissue and may close the entire wound, leaving only a vertical scar. If the damage is too severe, wind and pests will eventually kill the tree. Trees are natural lightning conductors, and are known to provide protection from lightning strikes to nearby buildings. When planted near a building, tall trees catch lightning, and the high biomass of the root system helps ground the lightning strike.

For this reason, you should not hide from the rain under trees during a thunderstorm, especially under tall or solitary trees in open areas.

Musical instruments are made from trees struck by lightning, attributing unique properties to them.

Lightning and electrical installations

Lightning strikes pose a major hazard to electrical and electronic equipment. When lightning directly hits the wires in the line, an overvoltage occurs, causing destruction of the insulation of electrical equipment, and high currents cause thermal damage to the conductors. To protect against lightning overvoltages, electrical substations and distribution networks are equipped with various types of protective equipment such as arresters, nonlinear surge arresters, and long-spark arresters. To protect against direct lightning strikes, lightning rods and lightning protection cables are used. Electromagnetic pulses created by lightning are also dangerous for electronic devices.

Lightning and aviation

Atmospheric electricity in general and lightning in particular pose a significant threat to aviation. A lightning strike on an aircraft causes a large current to spread through its structural elements, which can cause their destruction, fire in fuel tanks, equipment failures, and loss of life. To reduce risk, the metal elements of the outer skin of aircraft are carefully electrically connected to each other, and non-metallic elements are metallized. This ensures low electrical resistance of the housing. To drain lightning current and other atmospheric electricity from the body, aircraft are equipped with arresters.

Due to the fact that the electrical capacity of an aircraft in the air is small, the “cloud-to-aircraft” discharge has significantly less energy compared to the “cloud-to-ground” discharge. Lightning is most dangerous for a low-flying airplane or helicopter, since in this case the aircraft can play the role of a conductor of lightning current from the cloud to the ground. It is known that aircraft at high altitudes are relatively often struck by lightning, and yet, cases of accidents for this reason are rare. At the same time, there are many known cases of aircraft being struck by lightning during takeoff and landing, as well as while parked, which resulted in disasters or destruction of the aircraft.

Lightning and surface ships

Lightning also poses a very big threat to surface ships due to the fact that the latter are elevated above the sea surface and have many sharp elements (masts, antennas) that are concentrators of electric field strength. In the days of wooden sailing ships with a high specific resistance of the hull, a lightning strike almost always ended tragically for the ship: the ship burned down or was destroyed, and people died from electric shock. Riveted steel ships were also vulnerable to lightning. The high resistivity of the rivet seams caused significant local heat generation, which led to the occurrence of an electric arc, fires, destruction of the rivets and the appearance of water leaks in the body.

The welded hull of modern ships has low resistivity and ensures safe spreading of lightning current. The protruding elements of the superstructure of modern ships are reliably electrically connected to the hull and also ensure the safe spread of lightning current.

Human activities that cause lightning

During a ground-based nuclear explosion, a fraction of a second before the arrival of the boundary of the fiery hemisphere, several hundred meters (~400-700 m when compared with an explosion of 10.4 Mt) from the center, the gamma radiation that reaches it produces an electromagnetic pulse with a intensity of ~100-1000 kV/ m, causing lightning discharges striking from the ground upward before the arrival of the border of the fiery hemisphere.

Notes

Ermakov V.I., Stozhkov Yu.I. Physics of thunderclouds // Physical Institute named after. P.N. Lebedeva, RAS, M. 2004: 37
Cosmic rays blamed for lightning Lenta.Ru, 09.02.2009
Red Elves and Blue Jets
ELVES, a primer: Ionospheric Heating By the Electromagnetic Pulses from Lightning
Fractal Models of Blue Jets, Blue Starters Show Similarity, Differences to Red Sprites
V.P. Pasko, M.A. Stanley, J.D. Matthews, U.S. Inan, and T.G. Wood (March 14, 2002) "Electrical discharge from a thundercloud top to the lower ionosphere," Nature, vol. 416, pages 152-154.
The appearance of UFOs was explained by sprites. lenta.ru (24.02.2009). Archived from the original on August 23, 2011. Retrieved January 16, 2010.
John E. Oliver Encyclopedia of World Climatology. - National Oceanic and Atmospheric Administration, 2005. - ISBN 978-1-4020-3264-6
. National Oceanic and Atmospheric Administration. Archived
. NASA Science. Science News. (December 5, 2001). Archived from the original on August 23, 2011. Retrieved April 15, 2011.
K. BOGDANOV “LIGHTNING: MORE QUESTIONS THAN ANSWERS.” “Science and Life” No. 2, 2007
Zhivlyuk Yu.N., Mandelstam S.L. On the temperature of lightning and the force of thunder // JETP. 1961. T. 40, issue. 2. pp. 483-487.
N. A. Kun “Legends and Myths of Ancient Greece” LLC “AST Publishing House” 2005-538, p. ISBN 5-17-005305-3 Pages 35-36.

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