What is lightning? How is it formed and where does this natural phenomenon come from. Class hour on the topic: “Rain as a physical phenomenon The nature of the formation of lightning physics

The most interesting of them are presented in this article.

Linear lightning (cloud-ground)

How to get such lightning? Yes, it's very simple - all that is required is a couple of hundred cubic kilometers of air, a height sufficient for the formation of lightning and a powerful heat engine - well, for example, the Earth. Ready? Now take the air and sequentially begin to heat it. When it starts to rise, with each meter of rise, the heated air cools, gradually becoming colder and colder. Water condenses into ever larger droplets, forming thunderclouds.

Remember those dark clouds above the horizon, at the sight of which the birds fall silent and the trees stop rustling? So, these are the thunderclouds that give rise to lightning and thunder.

Plasma forms peculiar channels, which, when connected to the ground, serve as an excellent conductor for electricity. Clouds are constantly discharged through these channels, and we see the external manifestations of data atmospheric phenomena in the form of lightning.

By the way, the air temperature in the place where the charge (lightning) passes reaches 30,000 degrees, and the speed of lightning propagation is 200,000 kilometers per hour. In general, a few lightning bolts were enough to power a small town for several months.

Lightning earth-cloud

And there are such lightning. They are formed as a result of the accumulating electrostatic charge on top of the tallest object on earth, which makes it very "attractive" for lightning.

Such lightning is formed as a result of “breaking through” the air gap between the top of a charged object and bottom thundercloud.The higher the object, the more likely it is to be struck by lightning. So they say the truth - you should not hide from the rain under tall trees.

lightning cloud-cloud

Yes, individual clouds can “exchange” with lightning, striking each other with electric charges. It's simple - since the upper part of the cloud is positively charged, and the lower part is negatively charged, nearby thunderclouds can shoot each other with electric charges.

It is quite common for lightning to break through one cloud, and much rarer for lightning to travel from one cloud to another.

Horizontal zipper

This lightning does not hit the ground, it spreads horizontally across the sky. Sometimes such lightning can spread along clear sky coming from a single thundercloud. Such lightning is very powerful and very dangerous.

Tape zipper

This lightning looks like several lightning bolts running parallel to each other. There is no mystery in their formation - if a strong wind blows, it can expand the plasma channels, which we wrote about above, and as a result, such a differentiated lightning is formed.

Beaded (dotted zipper)

This is a very, very rare lightning, it exists, yes, but how it is formed is still anyone's guess. Scientists suggest that dotted lightning is formed as a result of the rapid cooling of some sections of the lightning track, which turns ordinary lightning into dotted lightning. As you can see, this explanation clearly needs to be improved and supplemented.

sprite lightning

Most of all, they look like jellyfish, right? The height of the formation of such lightning is about 100 kilometers. So far, it is not very clear what they are. Here are photos and even videos of unique sprite lightning. Very beautiful.

Ball lightning

Some people claim that ball lightning does not exist. Others post videos of fireballs on YouTube and prove it's all real. In general, scientists are not yet firmly convinced of the existence of ball lightning, and the most famous proof of their reality is a photo taken by a Japanese student.

Saint Elmo's fires

This, in principle, is not lightning, but simply the phenomenon of a glow discharge at the end of various sharp objects. The fires of St. Elmo were known in antiquity, now they are described in detail and captured on film.

Volcanic lightning

These are very beautiful lightning bolts that appear during a volcanic eruption. It is likely that the charged gas-dust dome, penetrating several layers of the atmosphere at once, causes disturbances, since it itself carries a rather significant charge. It all looks very beautiful, but creepy. Scientists do not yet know exactly why such lightning is formed, and there are several theories at once, one of which is outlined above.

Here are some interesting facts about lightning that are not often published:

* Typical lightning lasts about a quarter of a second and consists of 3-4 discharges.
* An average thunderstorm travels at a speed of 40 km per hour.
* There are 1,800 thunderstorms in the world right now.
* The US Empire State Building is struck by lightning an average of 23 times a year.
* Lightning strikes aircraft on average once every 5-10 thousand flight hours.
* The probability of being killed by lightning is 1 in 2,000,000. Each of us has the same chance of dying from falling out of bed.
* The probability of seeing ball lightning at least once in a lifetime is 1 in 10,000.
* People who were struck by lightning were considered marked by God. And if they died, they supposedly went straight to heaven. In ancient times, victims of lightning were buried at the place of death.

What should you do when lightning approaches?

In the house

* Close all windows and doors.
* Unplug all electrical appliances. Do not touch them, including phones, during thunderstorms.
* Keep away from bathtubs, faucets and sinks as metal pipes can conduct electricity.
* If ball lightning has flown into the room, try to get out quickly and close the door on the other side. If you can't, at least freeze in place.

On the street

* Try to go into the house or car. Do not touch metal parts in the car. The car should not be parked under a tree: suddenly lightning will strike it and the tree will fall right on you.
* If there is no shelter, go out into the open and, bending over, snuggle up to the ground. But you can't just lie down!
* In the forest, it is better to hide under low bushes. NEVER stand under a free-standing tree.
* Avoid towers, fences, tall trees, telephone and electrical wires, bus stops.
* Stay away from bicycles, barbecues, other metal objects.
* Keep away from the lake, river or other bodies of water.
* Remove all metal from yourself.
* Do not stand in the crowd.
* If you are in an open area and you suddenly feel your hair stand on end, or hear a strange noise coming from objects (that means lightning is about to strike!), bend forward with your hands on your knees (but not on the ground). The legs should be together, the heels pressed against each other (if the legs do not touch, the discharge will pass through the body).
* If a thunderstorm caught you in a boat and you no longer have time to swim to the shore, bend down to the bottom of the boat, join your legs and cover your head and ears.

How many types of lightning are there in reality? It turns out that there are more than ten species, and the most interesting of them are given in this article. Naturally, there are not only bare facts here, but also real photos real lightning.

So, the types of lightning will be considered in order, from the most common linear lightning to the rarest sprite lightning. Each type of lightning is given one or more photos that help to understand what such lightning really is.

L frost lightning (cloud-earth)

Scientists believe that lightning is formed as a result of the distribution of electrons in the cloud, usually positively charged from the top of the cloud, and negatively from. The result is a very powerful capacitor that can be discharged from time to time as a result of the abrupt transformation of ordinary air into plasma (this is due to the increasingly strong ionization of atmospheric layers close to thunderclouds). Plasma forms peculiar channels, which, when connected to the ground, serve as an excellent conductor for electricity. Clouds are constantly discharged through these channels, and we see the external manifestations of these atmospheric phenomena in the form of lightning.

And there are such lightning. They are formed as a result of the accumulating electrostatic charge on top of the tallest object on earth, which makes it very "attractive" for lightning. Such lightnings are formed as a result of "piercing" the air gap between the top of a charged object and the bottom of a thundercloud.

The higher the object, the more likely it is to be struck by lightning. So they say the truth - you should not hide from the rain under tall trees.

It is quite common for lightning to break through one cloud, and much rarer for lightning to travel from one cloud to another.

This lightning does not hit the ground, it spreads horizontally across the sky. Sometimes such lightning can spread across a clear sky, coming from a single thundercloud. Such lightning is very powerful and very dangerous.

So far, we have only talked about what happens below the clouds, or at their level. But it turns out that some types of lightning are higher than clouds. They have been known since the advent of jet aircraft, but these lightning bolts were photographed and filmed only in 1994. Most of all, they look like jellyfish, right? The height of the formation of such lightning is about 100 kilometers. So far, it is not very clear what they are.

Here are photos and even videos of unique sprite lightning. Very beautiful.

These are very beautiful lightning bolts that appear during a volcanic eruption. It is likely that the charged gas-dust dome, penetrating several layers of the atmosphere at once, causes disturbances, since it itself carries a rather significant charge. It all looks very nice, but creepy. Scientists do not yet know exactly why such lightning is formed, and there are several theories at once, one of which is outlined above.

Here are some interesting facts about lightning that are not often published:

* Typical lightning lasts about a quarter of a second and consists of 3-4 discharges.

* An average thunderstorm travels at a speed of 40 km per hour.

* There are 1,800 thunderstorms in the world right now.

* The US Empire State Building is struck by lightning an average of 23 times a year.

* Lightning strikes aircraft on average once every 5-10 thousand flight hours.

* The probability of being killed by lightning is 1 in 2,000,000. Each of us has the same chance of dying from falling out of bed.

* The probability of seeing ball lightning at least once in a lifetime is 1 in 10,000.

* People who were struck by lightning were considered marked by God. And if they died, they supposedly went straight to heaven. In ancient times, victims of lightning were buried at the place of death.

What should you do when lightning approaches?

In the house

On the street

* Try to go into the house or car. Do not touch metal parts in the car. The car should not be parked under a tree: suddenly lightning will strike it and the tree will fall right on you.
* If there is no shelter, go out into the open and, bending over, snuggle up to the ground. But you can't just lie down!
* In the forest, it is better to hide under low bushes. NEVER stand under a free-standing tree.
* Avoid towers, fences, tall trees, telephone and electrical wires, bus stops.
* Stay away from bicycles, barbecues, other metal objects.
* Keep away from the lake, river or other bodies of water.
* Remove all metal from yourself.
* Do not stand in the crowd.
* If you are in an open area and you suddenly feel your hair stand on end or hear a strange noise coming from objects (that means lightning is about to strike!), bend forward with your hands on your knees (but not on the ground). The legs should be together, the heels pressed against each other (if the legs do not touch, the discharge will pass through the body).
* If a thunderstorm caught you in a boat and you no longer have time to swim to the shore, bend down to the bottom of the boat, join your legs and cover your head and ears.

Lightning is one of those natural phenomena that have long inspired 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 which are quite large. The upper part can be located at an altitude of 7 kilometers, and the lower one - only 500 meters above the ground. Considering the atmospheric air temperature, we can conclude that at a level of 3-4 km, the water freezes and turns into ice floes, which, colliding with each other, are electrified. Those that have the largest size receive a negative charge, and the smallest - a positive one. Based on their weight, they are evenly distributed in the cloud by layers. Approaching each other, they form a plasma channel, from which an electric spark, called lightning, is obtained. 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 109 to 1010 joules of energy. Such a colossal amount of electricity is mostly 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 high temperature inside the zipper, it can reach 2000 degrees. The time of impact with 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 most powerful natural discharge of current is obtained, which brings death to everything that it touches. All existing species lightning are very dangerous, and meeting with them is extremely undesirable for a person.

Thunder formation

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

What are lightning

It turns out they are all different.

1. Line lightning - the most common variety. An electric peal looks like an overgrown tree turned upside down. Several thinner and shorter "processes" depart from the main canal. The length of such a discharge can reach 20 kilometers, and the current strength is 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 a change in electric and magnetic fields, radio waves are also emitted. Such a roll is most likely to be found closer to the equator. IN temperate latitudes he appears very rarely. If there is lightning in the cloud, then a foreign object that violates the integrity of the shell, such as an electrified aircraft or a metal cable, can also induce it to get out. The length can vary from 1 to 150 kilometers.

3. Ground lightning - this species goes through several stages. On 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 action of an electric field, elementary particles acquire high speeds and head towards the earth, colliding with the molecules that make up the air. Thus, there are electron avalanches, otherwise called streamers. They are channels that, merging with each other, cause a bright, thermally insulated lightning. It reaches the ground in the form of a small ladder, 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 passed its way, it ends its movement for several tens of microseconds, while the light weakens. After that, the next stage begins: the repetition of the path traveled. The most recent discharge surpasses all the previous ones in brightness, the current strength in it can reach hundreds of thousands of amperes. The temperature inside the channel fluctuates around 25,000 degrees. This type of lightning is the longest, so the consequences can be devastating.

Pearl Lightning

When answering the question of what kind of lightning 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 now it looks like balls that are at a distance from each other and resemble beads made of precious material. Such lightning is accompanied by the loudest and rolling 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 species, but the fact of its appearance even in sunny weather has been recorded.

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

Lightning diameter ranges from a few centimeters to a meter. As for the 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 suddenly change its trajectory and just as suddenly disappear, releasing huge energy, due to which melting or even destruction of various objects occurs. She lives from ten seconds to several hours.

lightning sprite

More recently, in 1989, scientists discovered another type of lightning, which was called sprite. The discovery happened quite by accident, because the phenomenon is extremely rare and lasts only tenths of a second. They are distinguished from others by the height at which they appear - approximately 50-130 kilometers, while other subspecies do not overcome the 15-kilometer line. Also, the lightning sprite has a huge diameter, which reaches 100 km. They appear vertical and flash in clusters. 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 health and even human life. To avoid electric shock, the following rules should be followed in open areas:

In this situation, the highest objects fall into the risk group, so open areas should be avoided. To become lower, it is best to sit down and put your head and chest on your knees, in case of defeat, this posture will protect all vital organs. In no case should you lie flat, so as not to increase the area of \u200b\u200ba possible hit.
Also, do not hide under tall trees and unprotected structures or metal objects (for example, a picnic shed) will be undesirable shelter.
During a thunderstorm, you should immediately get out of the water, because it is a good conductor. Getting into it, a lightning discharge can easily spread to a person.
Under no circumstances should you use your 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

Indoors, too, there is a danger of injury.

If a thunderstorm starts outside, the first thing to do is close all windows and doors.
All electrical appliances must be turned off.
Stay away from wired telephones 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 get into the room, you must immediately leave it and close all windows and doors. If these actions are not possible, it is better to stand still.

Nature is still beyond the control of man and carries many dangers. All types of lightning are, in essence, the most powerful electrical discharges, which are several times more powerful than all artificially created current sources by man.

""physical phenomenon""

A giant electrical spark discharge in the atmosphere, usually manifested by a bright flash of light and accompanying thunder. The electrical nature of lightning was revealed in the studies of the American physicist B. Franklin, on the basis of which an experiment was carried out to extract electricity from a thundercloud.

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

The process of ground lightning development consists of several stages. At the first stage, in the zone where the electric field reaches a critical value, impact ionization begins, initially created by free electrons, which are always present in a small amount in the air, which, under the action of an electric field, acquire significant velocities towards the ground and, colliding with air atoms, ionize their. That. electron avalanches appear, turning into filaments of electric discharges - streamers, which are well-conducting channels, which, merging, give rise to a bright thermally ionized channel with high conductivity - a step leader.

The movement of the leader to the earth's surface occurs in steps of several tens of meters at a speed of ~ 5 * 10,000,000 m/sec, after which its movement stops for several tens of microseconds, and the glow is greatly weakened; then, in the next stage, the leader again advances several tens of meters. A bright glow covers all the steps passed; then a stop and a weakening of the glow follow again. These processes are repeated when the leader moves to the earth's surface at an average speed of 2*100,000 m/s. As the leader moves towards the ground, the field strength at its end increases and under its action a response streamer is ejected from the objects protruding on the Earth's surface, connecting with the leader.

lightning shapes

Line lightning

A discharge of linear lightning occurs between clouds, inside a cloud, or between a cloud and the ground, and usually has a length of about 2-3 km, but there are lightnings up to 20-30 km long.

It looks like a broken line, often with numerous branches. Lightning color - white, yellow, blue or reddish

Most often, the diameter of the thread of such lightning reaches a couple of tens of centimeters. This type is the most common; we see it most often. Linear lightning appears when the electric field of the atmosphere is up to 50 kV / m, the potential difference in its path can reach hundreds of millions of volts. The lightning current of this kind is about 10 thousand amperes. A thundercloud that produces a linear lightning discharge every 20 seconds has an electrical energy of 20 million kW. Potential Electric Energy stored by such a cloud is equal to the energy of a megaton bomb.

This is the most common form of lightning.

Flat zipper

Flat lightning looks like a scattered flash of light on the surface of clouds. Thunderstorms, accompanied only by flat lightning, are classified as weak, and they are usually observed only in early spring or late autumn.

Tape zipper

Ribbon lightning - several identical zigzag discharges from clouds to the ground, parallel shifted relative to each other with small or no gaps.

Bead lightning

A rare form of electrical discharge during a thunderstorm, in the form of a chain of luminous dots.The lifetime of bead lightning is 1–2 seconds. It is noteworthy that the trajectory of bead lightning often has a wave-like character. Unlike linear lightning, the trail of bead lightning does not branch - this is a distinctive feature of this species.

rocket lightning

Rocket lightning is a slowly developing discharge, lasting 1–1.5 seconds. Rocket lightning is very rare.

Ball lightning

Ball lightning- a bright luminous electric charge of various colors and sizes. Near the ground, it most often looks like a ball with a diameter of about 10 cm, less often it has the shape of an ellipsoid, a drop, a disk, a ring, and even a chain of connected balls. The duration of the existence of ball lightning is from several seconds to several minutes, the color of the glow is white, yellow, light blue, red or orange. Usually this type of lightning moves slowly, almost silently, accompanied by only a slight crackling, whistling, buzzing or hissing. Ball lightning can penetrate enclosed spaces through cracks, pipes, windows.

A rare form of lightning, according to statistics, there are 2-3 ball lightning per thousand ordinary lightning.

The nature of ball lightning is not fully understood. There are many hypotheses about the origin of ball lightning, from scientific to fantastic.

curtain zipper

Curtain lightning looks like a wide vertical band of light, accompanied by a low low rumble.

Volumetric lightning

Bulk lightning is a white or reddish flash with low translucent clouds, with a strong crackling sound “from everywhere”. It is more often observed before the main phase of a thunderstorm.

strip zipper

Strip lightning - strongly resembles the aurora, "laid on its side" - horizontal stripes of light (3-4 stripes) are grouped on top of each other.

Elves, jets and sprites

Elves (English Elves; Emissions of Light and Very Low Frequency Perturbations from Electromagnetic Pulse Sources) are huge, but dimly luminous flash-cones with a diameter of about 400 km, which appear directly from the top of a thundercloud.

The jets are blue tube-cones.

Sprites - a kind of lightning, beating up from the cloud. For the first time this phenomenon was recorded in 1989 by accident. Very little is known about the physical nature of sprites.

Jets and Elves form from the tops of the clouds to the lower edge of the ionosphere (90 kilometers above the Earth's surface). The duration of these aurora is a fraction of a second. To photograph such short-lived phenomena, high-speed imaging equipment is needed. Only in 1994, flying in an airplane over a big thunderstorm, did scientists manage to capture this amazing sight.

Other phenomena

flashes

Flashes are white or blue silent flashes of light observed at night in partly cloudy or clear weather. Flashes usually occur in the second half of summer.

Zarnitsa

Zarnitsy - reflections of distant high thunderstorms, visible at night at a distance of up to 150 - 200 km. The sound of thunder during lightning is not heard, the sky is cloudy.

Volcanic Lightning

There are two types of volcanic lightning. One arises at the crater of the volcano, and the other, as seen in this image of the Puyehue volcano in Chile, electrifies the smoke of the volcano. Water and frozen ash particles in the smoke rub against each other, and this causes static discharges and volcanic lightning.

Lightning Catatumbo

Catatumbo lightning is an amazing phenomenon that is observed in only one place on our planet - at the confluence of the Catatumbo River into Lake Maracaibo ( South America). The most surprising thing about this type of lightning is that its discharges last about 10 hours and appear at night 140-160 times a year. Catatumbo lightning is clearly visible at a fairly long distance - 400 kilometers. Lightnings of this kind were often used as a compass, from which people even nicknamed the place of their observation - “Maracaibo Lighthouse”.

Most say that Catatumbo lightning is the largest single ozone generator on Earth, because. winds coming from the Andes cause thunderstorms. Methane, which is abundant in the atmosphere of these wetlands, rises to the clouds, fueling lightning discharges.

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

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

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

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

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

Riddle of ball lightning ……………………………………………...13

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

Types of ranks .................................................. ................................. 26

Spark Discharge .................................................. .............................. 26

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

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

References .................................................................. 39

The choice of the topic of my essay is due not only to personal interest, but also to 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 - that's all that science has. 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 phenomenon of nature. It makes it possible to observe the electrical discharge in gaseous environment at a voltage of several hundred million volts and a distance between the electrodes of several kilometers. The purpose of this essay is to consider the causes of lightning, the study of various types of electric charges. The issue of lightning protection is also considered in the abstract. People have long understood the harm that a lightning strike can bring, and have come up with protection from it.

Lightning has long been of interest to scientists, but in our time 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 originally 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 long tried to comprehend the nature of lightning and thunder, to understand their natural causes. In ancient times, Aristotle thought about this. Lucretius thought about the nature of lightning. His attempts to explain the thunder as a consequence of the fact that "the clouds collide there under the pressure of the winds" seem very naive.

For many centuries, including the Middle Ages, it was believed that lightning is a fiery vapor trapped in the water vapor of clouds. Expanding, it breaks through them in the most weak 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 when a thunderstorm approached.

Experiment: A pointed wire was fastened to the cross 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 pointed wire began to extract an electric charge from it, and the kite, along with the towline, became electrified. After the rain wets the kite and string, thus making them free to conduct an electric charge, one can observe how the electric charge will "drain" when the finger approaches.

Simultaneously with Franklin, M.V. Lomonosov and G.V. Richman.

Thanks to their research in the middle of the 18th century, the electrical nature of lightning was proved. Since that time, it has become clear that lightning is a powerful electrical discharge that occurs when the clouds are sufficiently electrified.

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

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

How to trigger a lightning bolt? It is very difficult to study what will happen in an incomprehensible place and when. Namely, during for long years worked scientists investigating the nature of lightning. It is believed that the storm 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. For this, B. Franklin launched a kite during a thunderstorm, ending in 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 clouds to the ground. Franklin's experiments were extremely dangerous, and one of those who tried to repeat them, the Russian academician G. V. Richman, died in 1753 from a lightning strike.

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

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

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

Lightning is a "hello" from space and a source of X-rays. However, the cloud itself is not able to electrify itself so as to cause a discharge between its lower part and the earth. The electric field strength in a thundercloud never exceeds 400 kV/m, and electrical breakdown in air occurs at a strength greater than 2500 kV/m. Therefore, for lightning to occur, something else is needed besides an electric field. In 1992, the Russian scientist A. Gurevich from the Physical Institute. P. N. Lebedeva of the Russian Academy of Sciences (FIAN) suggested that cosmic rays, high-energy particles that fall on the Earth from space at near-light speeds, can 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 earth, the electrons are accelerated to near-light speeds, ionizing the path of their movement and, thus, causing an avalanche of electrons moving with them to the earth. 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 x-ray radiation, the intensity of which can be up to 250,000 electron volts, which is about twice as high as that used in a chest x-ray.

a) Most lightning occurs between clouds and the ground, however, there are lightnings that occur between clouds. All these lightnings are called linear. The length of an individual linear lightning can be measured in kilometers.

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

c) It was noticed that in some cases the flash of lightning breaks up into separate luminous sections 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 protracted discharge, after which the glow would seem to be brighter in the place where the channel bends in the direction of the observer, observing it with its end towards itself. And Yuman (1962) believed that this phenomenon should be considered as an example of the "ping effect", which consists in 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 is a series of pulses rapidly following each other. Each impulse is a breakdown of the air gap between the cloud and the ground, which occurs 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 a 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 in the lower part of the cloud - 105 ... 106 V / m.

Free electrons receive huge accelerations in such a field. These accelerations are directed downward, since the lower part of the cloud is negatively charged, while 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, colliding with atoms or molecules, they ionize them. As a result, new (secondary) electrons are born, which, in turn, are accelerated in the cloud field and then ionize new atoms and molecules in collisions. Entire avalanches of fast electrons arise, forming clouds at the very “bottom”, plasma “filaments” - a streamer.

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

This plasma channel, which develops 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, moreover, relatively regular ones, is not exactly known. There are several theories of step leaders.

In 1938 Schonlund put forward two possible explanations for the delay that causes the stepping nature of the leader. According to one of them, there should be a movement of electrons down the channel lead streamer (pilot). However, some of the electrons are captured by atoms and positively charged ions, so that it takes some time for new advancing electrons to enter before a potential gradient is created that is sufficient for the current to continue. According to another point of view, it takes time for positively charged ions to accumulate under the head of the leader channel and thus create a sufficient potential gradient across it. But the physical processes occurring near the head of the leader are quite understandable. The field strength under the cloud is quite large - it is V/m; in the region of space directly in front of the leader's head, it is even greater. In a strong electric field near the leader head, intense ionization of air atoms and molecules occurs. It occurs due, firstly, to the bombardment of atoms and molecules by fast electrons emitted from the leader (the so-called impact ionization), and, secondly, the absorption by atoms and molecules of photons of ultraviolet radiation emitted by the leader (photoionization). Due to the intense ionization of the air atoms and molecules encountered on the path of the leader, the plasma channel grows, and the leader moves towards the earth's surface.

Taking into account the 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 earth's surface. Now the cloud is connected to the ground by a plasma channel, which perfectly conducts current. The channel of ionized gas, as it were, short-circuited the cloud with the earth. This completes the first stage of development of the initial impulse.

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

It is essential 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, we conditionally divide the entire channel into several parts. As soon as the channel is formed (the head of the leader has reached the ground), first of all, the electrons that were in its lowest part jump down; therefore, the lower part of the channel is the first to glow and warm up. Then electrons from the next (higher up part of the channel) rush to the ground; the glow and heating of this part begin. And so gradually - from the bottom to the top - more and more electrons are included in the movement to the ground; as a result, the glow and heating of the channel propagate in the upward direction.

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

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

As discussed 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 follows a powerful pulse of the main current. After another pause, everything repeats. As a result, several powerful impulses are displayed, which we naturally perceive as single rank lightning, as a single bright flash (Fig. 3).

Ball Lightning Mystery

Ball lightning is absolutely different from ordinary (linear) lightning, neither in its appearance nor in the way it behaves. Ordinary lightning is short-lived; ball lives tens of seconds, minutes. Ordinary lightning is accompanied by thunder; ball is almost silent, its behavior has a lot of unpredictability (Fig. 4).

Ball lightning asks us a lot of mysteries, questions to which there is no clear answer. At present, one 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. CMM is a spherical object with a diameter of 5 ... 30 cm. The shape of the CMM changes slightly, taking on a pear-shaped or flattened spherical shape. Very rarely, BL was observed in the form of a torus.

2. CMM usually glows in orange, cases of violet color are noted. The brightness and nature of the glow are similar to the glow of red-hot charcoal, sometimes the intensity of the glow is compared with a weak electric light bulb. Against the background of homogeneous radiation, more brightly luminous regions (glare) appear and move.

3. The lifetime of BL is from a few seconds to ten minutes. The existence of CMM 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 anecdotal evidence of the observation of CMM during a thunderstorm without rain. There have been cases of observations of CMM over water bodies at a considerable distance from the coast or any objects.

5. 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 BL bounces off like a poorly inflated balloon or ends its existence.

6. Upon contact with steel objects, the CMM is destroyed, and a bright flash lasting several seconds is observed, accompanied by flying luminous fragments resembling metal welding. Steel objects upon subsequent inspection are slightly melted.

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

8. With a brief touch of the CMM on the skin of a person, minor burns are recorded. Severe burns and even death were recorded at contacts that ended in a flash or explosion.

10. There is evidence of observation of the process of the emergence of CMM 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 about 10 cm. In all such cases, the BL exists for several seconds and is destroyed with a characteristic pop without significant harm to the objects present and surroundings.

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.

"Plasma is very similar to a gas in a number of ways. 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 the existence of matter at temperatures of the order of 10,000 degrees and above. Up to 100,000 degrees, this is cold plasma, and above - hot."

Plasma confinement in a given open volume is a complex technical problem.

"Experiments on experimental thermonuclear installations are going on in different countries, but it has not yet been possible to achieve the required temperature and plasma confinement time." It's about about a time not exceeding 1 s.

It is quite obvious that a plasma in air cannot create a spherical structure, let alone keep it for several minutes.

Let us form 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.

No wonder ball lightning tends to go down, the difference between the force of gravity and the buoyant (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") only relatively slightly exceeds the temperature of the surrounding air, reaching, apparently, 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 electric charges accumulated in other conductors.

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

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

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

Ball lightning injuries to people and animals also seem to be related to the current pulses it causes.

The energy reserve of ball lightning can range from several kilojoules to several tens of kilojoules, in some cases (especially when large sizes lightning), perhaps up to a hundred kilojoules. Energy density 1-10 kJ. However, the effects of an explosion can 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 the 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 a 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 when strong wind), 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 also restored 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 substance droplets from the surface, similar to liquid splashes.

The existence of non-spherical ball lightning (pear-shaped, elliptical) may be due to 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 down from its surface in different ways). The motion of ball lightning in conditions of indifferent equilibrium, in which the force of gravity is balanced Archimedean force, is defined as electric fields and air movement.

There is a correlation between lifetime and lightning size.

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

Analyzing observations, we can assume that ball lightning appears where a significant electric 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 (quiet extinction). The nature of the explosion of ball lightning is not entirely clear.

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

The power of the emitted light is of the order of several watts. Since the temperature of lightning is low, its visible radiation has a non-equilibrium nature. Perhaps lightning also emits some ultraviolet radiation, the absorption of which in the air can explain the blue halo around it.

The heat exchange of ball lightning with the environment occurs through the emission of a significant amount infrared radiation. If ball lightning really can be assigned a temperature of 500-600 K, then the power of the equilibrium thermal radiation, emitted by lightning with an average diameter (cm), is about 0.5-1 kW and the maximum radiation lies in the wavelength range of 5-10 microns.

In addition to infrared and visible radiation, ball lightning can emit a rather strong non-equilibrium 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 outside. It is assumed that lightning somehow receives the energy accumulated in clouds and clouds, and the heat release in the channel itself turns out to be insignificant, so that all the transferred energy is concentrated in the volume of ball lightning, causing it to glow. Another group includes hypotheses according to which ball lightning becomes independent an existing facility. This object consists of a certain substance, within which processes occur, leading 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 you know, 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 sources of energy in nature that are still unknown to us, then on the basis of the law of conservation of energy we have to accept that during the glow energy is continuously supplied to ball lightning, and we are forced to look for a source outside the volume of 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 input in the form of radio wave radiation.

He suggested that artificial ball lightning can be created using a powerful stream of radio waves focused into a limited area of space (If 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 well-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.

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

According to it, in a thunderstorm, under the action of a potential difference, a directed drift of electrons from clouds to the ground begins. Along the way, electrons, of course, collide with gas molecules that make up air, and contrary to common sense- the less often, the higher the speed of the electron. As a result, individual atoms that have reached a certain critical speed roll down, as if from a hill. This "hill effect" rebuilds the army of charged particles. They begin to roll down not in a disorderly crowd, but in ranks, just as the waves of the sea surf roll. Only this "surf" has an enormous speed - 1000 km / s! The energy of such waves, as Hazen's calculations show, is quite enough to, overtaking the 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 swim up under the action of the Archimedean force; on the other hand, under the action of electrostatic forces, the ball is attracted to the wet 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 jumps. They can be caused either by a strong gust of wind or a change in the direction of the electron avalanche.

An explanation was found for another fact: ball lightning tends to get inside buildings. Any structure, especially stone, raises in this place the groundwater level, which means that 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? Electron drift is also to blame here. If too much energy is supplied to the spherical "vessel", it eventually bursts due to overheating or, having fallen into the region of increased electrical conductivity, is discharged, like an ordinary linear lightning. If the electron drift dies out for some reason, the ball lightning quietly fades away, dissipating its charge in the surrounding space.

A.M. Khazen 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.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 DC voltage pulse, vary the frequency and amplitude of the microwave field, then at the end ends at the free end of the wire, even after turning off the alternating field, a luminous plasma bunch should remain and, possibly, separate from the conductor.

The need for a large amount of energy hinders 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 propose it. And in the mid-70s, B.M. Smirnov developed it in detail. It is assumed that ball lightning consists of ordinary air (having a temperature of about 100? above the temperature of the surrounding atmosphere), a small admixture of ozone and nitrogen oxides, etc. Fundamentally important role ozone plays here, which is formed during the discharge of ordinary lightning; its concentration is about 3%.

The disadvantage of the considered physical model is also the impossibility of explaining the stable form of ball lightning, 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 expended on their formation determines the energy reserve of ball lightning. It is released during the recombination of ions. Due to the electrostatic (Coulomb) forces acting between the ions, the volume filled with ions will have surface tension, which determines the stable globular form of lightning.

Stakhanov, like many other physicists, proceeded from the fact that lightning consists of matter in the state of plasma. Plasma is similar to the gaseous state with the only difference: the molecules of the substance in the plasma are ionized, that is, they have lost (or, on the contrary, acquired extra) electrons and ceased to be 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. Therefore, in a plasma, molecules tend to regain their lost charge by recombining with detached electrons. But after recombination, the plasma will turn into an ordinary gas. Plasma life can be maintained only as long as something interferes with recombination - as a rule, a very high temperature.

If ball lightning is a plasma ball, then it must be hot. This is how the proponents of plasma models argued before Stakhanov. And he noticed that there is another possibility. Ions, that is, molecules that have lost or captured an extra electron, can attract ordinary neutral water molecules to themselves and surround themselves with a strong "water" shell that locks extra electrons inside and prevents them from reuniting with their hosts. This is possible because the 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, ultrahigh 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, so Professor Stakhanov's hypothesis is called a cluster one.

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 General Physics Institute of the Russian Academy of Sciences, which includes Prof. Sergei Yakovlenko, have recently obtained startling 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 itself, disorder spontaneously increases, that is, in the case of ball lightning, recombination will occur by itself if it is not somehow interfered with. From the results of computer simulation 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", there will be no recombination, 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 a self-existing body (without a continuous supply of energy from external sources), consisting of heavy positive and negative ions, the recombination of which is strongly inhibited due to ion hydration.

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

In 2000, Nature magazine featured the work of New Zealand chemists John Abrahamson and James Dinnis. They showed that when lightning strikes soil containing silicates and organic carbon, a ball of silicon and silicon carbide fibers is formed. These fibers slowly oxidize and begin to glow - a fireball flares up, heated to 1200-1400 ° C. Ball lightning usually melts silently, but it happens that they explode. According to Abrahamson and Dinnis, this happens if the initial temperature of the coil 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 the scheme of the installation, on which they managed to obtain ball discharges, which they called "plasmoids" and resembled ball lightning. The experiments could well be reproduced, only plasmoids existed for no more than a second.

In February 2006, a message arrived from Tel Aviv University. Physicists Vladimir Dikhtyar and Eli Yerby observed luminous balls of gas in the laboratory, in many ways resembling those strange lightning bolts. To generate them, Dikhtyar and Yerby heated a silicon substrate in a 600-watt microwave field until it evaporated. A yellowish-red ball about 3 centimeters in diameter appeared in the air, consisting of ionized gas (as you can see, noticeably smaller than ball lightning). It slowly floated 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 glided along them, but it could not penetrate the window glass. In the experiments of Dikhtyar and Yerby, glass broke when it came into contact with a fireball.

Obviously, ball lightning in nature is generated not by microwave fields, but by electric discharges. In any case, Israeli scientists have demonstrated that the study of such lightning is acceptable in the laboratory and that the results of experiments can be used to create new technologies for processing materials, in particular, for the deposition of ultrathin films.

The number of different hypotheses about the nature of ball lightning far exceeds a hundred, but we have analyzed 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 have been understood, this problem cannot be considered solved - many secrets and mysteries remain, and there are no specific ways to create it in the laboratory.

This discharge is characterized by an intermittent form (even when using direct current sources). It occurs in a gas usually at pressures of the order of atmospheric. In natural natural conditions spark discharge is observed in the form of lightning. Externally, the spark discharge is a beam 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, as well as from any point in between. The channels developing from the positive electrode have clear filamentous outlines, while those developing from the negative electrode have diffuse edges and smaller branching.

Because 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 is filled with a "spark" channel, the gap resistance becomes very small, a short-term current pulse of high strength passes through the channel , during which only a small resistance falls on the 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 the 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 voltage rise time is the longer, the greater the capacitance C between the electrodes. Therefore, the inclusion of 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 increase. With a large capacitance C, the spark channel glows brightly and has the form of wide bands. The same thing happens when the power of the current source is increased. Then one speaks of a condensed spark discharge, or a condensed spark. The maximum current in a pulse during a spark discharge varies over a wide range, depending on the parameters of the discharge circuit and conditions in the discharge gap, reaching several hundred kiloamperes. With a further increase in the power of the source, the spark discharge turns into an arc discharge.

As a result of the passage of a current pulse through the channel, a spark is released in the channel a large number of energy (of the order of 0.1 - 1 J for each centimeter of the channel length). With the release of energy, an abrupt increase in pressure in the surrounding gas is associated - the formation of a cylindrical shock wave, the temperature at the front of which is ~104 K. The spark channel expands rapidly, at a rate of the order of the thermal velocity of gas atoms. As the shock wave advances, the temperature at its front begins to fall, 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: characteristic crackling in weak discharges and powerful peals in the case of lightning.

At the time of the existence of the channel, especially at high pressures, a brighter glow of the spark discharge is observed. The glow brightness is non-uniform over the channel cross section and has a maximum at its center.

Consider the spark discharge mechanism.

At present, the so-called streamer theory of a spark discharge, confirmed by direct experiments, is considered generally accepted. Qualitatively, it explains the main features of the spark discharge, although quantitatively it cannot be considered complete. If an electron avalanche is born near the cathode, then ionization and excitation of gas molecules and atoms take place along its path. It is essential that the light quanta emitted by excited atoms and molecules, propagating towards the anode at the speed of light, themselves produce gas ionization and give rise to the first electron avalanches. In this way, weakly luminous 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 of time, a powerful flow of electrons rushes, forming a spark discharge channel. Since the conducting bridge is formed as a result of the merging of streamers that appear almost simultaneously, the time of its formation is much shorter than the time required for a separate electron avalanche to travel distances 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 huge accelerations in such a field. These accelerations are directed downward, since the lower part of the cloud is negatively charged, while 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, colliding with atoms or molecules, they ionize them. As a result, new (secondary) electrons are born, which, in turn, are accelerated in the cloud field and then ionize new atoms and molecules in collisions. Entire avalanches of fast electrons arise, forming at the very "bottom" clouds, plasma "filaments" - 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, which develops 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 rather a step leader. The fact is that the channel is formed not smoothly, but in jumps - "steps".

Why there are pauses in the leader's movement and, moreover, relatively regular ones, is not exactly known. There are several theories of step leaders.

In 1938 Schonlund put forward two possible explanations for the delay that causes the stepping nature of the leader. According to one of them, electrons must move down the channel of the leading streamer (pilot). However, some of the electrons are captured by atoms and positively charged ions, so that it takes some time for new advancing electrons to enter before a potential gradient is created that is sufficient for the current to continue. According to another point of view, it takes time 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 is based on the development of a glow discharge into an arc discharge. He considered a "corona discharge", similar to that of a tip, which exists around the leader channel not only at the channel head, but along its entire length. He explained that the conditions for the existence of an arc discharge would be established for some time after the channel had developed a certain distance and, consequently, the steps had appeared. This phenomenon has not yet been fully studied and there is no specific theory yet. But the physical processes occurring near the head of the leader are quite understandable. The field strength under the cloud is quite high - it is V/m; in the region of space directly in front of the leader's head, it is even greater. The increase in the field strength in this region is well explained in Fig. 4, where the dashed curves show the 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 air atoms and molecules occurs. It occurs due, firstly, to the bombardment of atoms and molecules by fast electrons emitted from the leader (the so-called impact ionization), and, secondly, to the absorption by atoms and molecules of photons of ultraviolet radiation emitted by the leader (photoionization). Due to the intense ionization of the air atoms and molecules encountered on the path of the leader, the plasma channel grows, and the leader moves towards the earth's surface.

Taking into account the 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 ground. Now the cloud is connected to the ground by a plasma channel, which perfectly conducts current. The channel of ionized gas, as it were, short-circuited the cloud with the earth. This completes the first stage of development of the initial impulse.

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

It is essential 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, we conditionally divide the entire channel into several parts. As soon as the channel is formed (the head of the leader has reached the ground), first of all, the electrons that were in its lowest part jump down; therefore, the lower part of the channel is the first to glow and warm up. Then electrons from the next (higher up part of the channel) rush to the ground; the glow and heating of this part begin. And so gradually - from the bottom to the top - more and more electrons are included in the movement to the ground; as a result, the glow and heating of the channel propagate in the upward direction.

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

However, a large charge is still preserved 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 swept. Arrow-shaped leaders are similar to steps of a stepped leader. However, since the ionized channel already exists, there is no need for a pilot and stages. Since the ionization in the channel of the swept leader is "older" than that of the step leader, the recombination and diffusion of charge carriers are more intense, 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 steps 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 passes between successive lightning strikes, the degree of ionization can be so low, especially in the lower part of the channel, that a new pilot is needed 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 subsequent main lightning strikes.

As discussed 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 follows a powerful pulse of the main current. After another pause, everything repeats. As a result, several powerful impulses are displayed, which we naturally perceive as a single lightning discharge, as a single bright flash.

Before the invention of electricity and lightning rods, people struggled with the devastating effects of lightning strikes with spells. In Europe, continuous bell ringing during a thunderstorm was considered an effective means of struggle. 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 invent effective method became US scientist Benjamin Franklin - the universal genius of his era (1706-1790).

How Franklin deflected lightning. Fortunately, most lightning strikes occur between clouds and therefore do not pose a threat. However, lightning is believed to kill more than a thousand people worldwide every year. At least in the United States, where such statistics are kept, about 1000 people are affected by lightning each 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 (Leiden jar), Pieter van Muschenbroek (1692-1761), in an article on electricity written for the famous French Encyclopedia, defended the traditional methods of preventing lightning - ringing bells and firing cannons, which, he believed, turned out to be quite efficient.

Benjamin Franklin, trying to protect the Capitol of the capital of Maryland, in 1775 attached a thick iron rod to the building, which towered several meters above the dome and was connected to the ground. The scientist refused to patent his invention, wishing that it would serve 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 met 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 broke lightning rods for pious reasons. A curious incident occurred in 1780 in the small town of Saint-Omer in northern France, where the townspeople demanded the removal of an iron lightning rod mast, and the case went to trial. The young lawyer who defended the lightning rod against the attacks of obscurantists built his defense on the fact that both the human mind and its ability to conquer the forces of nature are of divine origin. Everything that helps to save a life is for the good - the young lawyer argued. He won the process 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 coveted reproduction in the world, because it adorns the well-known hundred-dollar bill.

How you can protect yourself from lightning with a water jet and a laser. Recently it has been proposed new way fight against lightning. A lightning rod will be created from ... a jet of liquid, which will be shot from the ground directly into thunderclouds. The lightning liquid is a saline solution to which liquid polymers are added: the salt is intended to increase the electrical conductivity, and the polymer prevents the jet from "breaking up" into separate droplets. The jet diameter 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 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. A similar protection against a lightning discharge can be done with the help of a laser, the beam of which, by ionizing the air, will create a channel for an electric discharge away from crowds of people.

Can lightning lead us astray? Yes, if you use a compass. IN famous novel G. Melvila "Moby Dick" described just such a case when a lightning discharge, which created a strong magnetic field, remagnetized the compass needle. However, the ship's captain took a sewing needle, struck it to magnetize it, and replaced it with a broken compass needle.

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

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

Doctors believe that a person who survived a lightning strike (and there are many such people), even without severe burns to the head and body, can subsequently receive complications in the form of deviations in cardiovascular and neuralgic activity from the norm. However, it might do.

People have long understood the harm that a lightning strike can bring, and have come up with protection from it. But again, for some reason, they called it a lightning rod, although it “takes away” not thunder, but lightning. A lightning rod is an iron pole that is placed as high as possible. After all, lightning must first pave its way 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) object. When lightning "sees" a high iron pole nearby, prepared for it by people, it lays a path to it. A lightning rod is connected to the ground by a wire, and all the electricity of the lightning, without harming anyone, goes into the ground. But earlier, a long time ago, in cities and villages there were big fires from lightning strikes.

Rabbi Yehuda Nakhshoni cites a commentary by Rabbain Bakhya (died 1340) who believed that tower of babel was supposed to be a kind of lightning rod against 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 do not argue that he was really interested in this issue, managed to use the accumulated experience and give practical use to your ideas. However, as we can see, even at the time of the compilation of the Mishnah (1500 years before that), lightning rods were already used. Therefore, we can assume that the primacy attributed to Franklin is, in fact, rather doubtful. 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 man encounters everywhere.

At present modern level science and technology allows you to create a truly functionally reliable lightning protection system corresponding to the technical level.

There are about 32 billion lightning strikes on Earth every year, with damage estimated at $5 billion. In the United States alone, about 1,000 people suffer from lightning each year, 200 of whom die.

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

Ball lightning is a mysterious phenomenon of nature, the observations of which have been reported for several centuries. Great progress has been made in the study of this phenomenon in the last ten to fifteen years. The study of the mysterious phenomenon is progressing due to the development related areas 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 figured this out, we will find real what previously seemed exotic, and we will get qualitative representations that may have analogues in other countries. physical processes and phenomena. Obtaining such insights enriches science and is valuable in the studies under consideration. Such is the logic of the development of science in general, and the accumulated experience of 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 essay was fulfilled: the reasons for the occurrence of lightning were considered, different kinds electric charges, various types of protection are considered.

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