Lightning
We often think that electricity is something that is generated only in power plants, and certainly not in the fibrous masses of water clouds, which are so rarefied that you can easily stick your hand into them. However, there is electricity in the clouds, just as there is even in the human body.
All bodies are made of atoms - from clouds and trees to the human body. Every atom has a nucleus containing positively charged protons and neutral neutrons. The exception is the simplest hydrogen atom, in the nucleus of which there is no neutron, but only one proton.
Negatively charged electrons circulate around the nucleus. Positive and negative charges attract each other, so electrons revolve around the nucleus of an atom, like bees around a sweet pie. The attraction between protons and electrons is due to electromagnetic forces. Therefore, electricity is present everywhere we look. As we see, it is also contained in atoms.
Under normal conditions, the positive and negative charges of each atom balance each other, so bodies consisting of atoms usually do not carry any net charge - neither positive nor negative. As a result, contact with other objects does not cause an electrical discharge. But sometimes the balance of electrical charges in bodies can be disrupted. You may experience this yourself while at home on a cold winter day. The house is very dry and hot. You, shuffling with your bare feet, walk around the palace. Unbeknownst to you, some of the electrons from your soles transferred to the atoms of the carpet.
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Now you are carrying an electrical charge because the number of protons and electrons in your atoms is no longer balanced. Now try to grab the metal door handle. A spark will jump between you and her and you will feel an electric shock. What has happened is that your body, which does not have enough electrons to achieve electrical balance, seeks to restore balance through the forces of electromagnetic attraction. And it is restored. Between the hand and the door handle there is a flow of electrons directed towards the hand. If the room was dark, you would see sparks. Light is visible because electrons, when they jump, emit quanta of light. If the room is quiet, you will hear a slight crackling sound.
Electricity surrounds us everywhere and is contained in all bodies. Clouds in this sense are no exception. Against the background of the blue sky they look very harmless. But just like you in the room, they can carry an electrical charge. If so, beware! When the cloud restores the electrical balance within itself, a whole fireworks display breaks out.
Here's what happens: powerful air currents constantly circulate in a dark, huge thundercloud, pushing various particles together - grains of ocean salt, dust, and so on. Just as your soles, when rubbed against a carpet, are freed from electrons, particles in a cloud, when they collide, are freed from electrons, which jump to other particles. This is how charge redistribution occurs. Some particles that have lost their electrons have a positive charge, while others that have taken on extra electrons now have a negative charge.
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For reasons that are not entirely clear, heavier particles become negatively charged, while lighter particles become positively charged. Thus, the heavier lower part of the cloud becomes negatively charged. The negatively charged lower part of the cloud pushes electrons towards the ground, as like charges repel each other. Thus, a positively charged part of the earth's surface is formed under the cloud. Then, according to exactly the same principle that a spark jumps between you and the doorknob, the same spark will jump between the cloud and the ground, only very large and powerful - this is lightning. The electrons fly in a giant zigzag towards the ground, finding their protons there. Instead of a barely audible crackling sound, there is a strong clap of thunder.
Lightning is a spark discharge of static electricity accumulated in thunderclouds. Unlike discharges generated at work and in everyday life, electrical charges accumulated in clouds are disproportionately greater. Therefore, the energy of the spark discharge - lightning and the resulting currents is very high and poses a great danger to humans, animals, and buildings. Lightning is accompanied by a sound impulse - thunder. The combination of lightning and thunder is called a thunderstorm.
Storm- This is an exceptionally beautiful natural phenomenon. As a rule, after a thunderstorm the weather improves, the air becomes clear, fresh and clean, saturated with ions formed during lightning discharges. Despite this, it must be remembered that a thunderstorm in certain conditions can pose a great danger to humans. Every person should know the nature of the thunderstorm phenomenon, the rules of behavior during a thunderstorm and methods of protection against lightning. A thunderstorm is a complex atmospheric process and its occurrence is caused by the formation of cumulonimbus clouds. Heavy cloudiness is a consequence of significant atmospheric instability. A thunderstorm is characterized by strong winds, often intense rain and snow, sometimes with hail. Before a thunderstorm, “in an hour or two,” the atmospheric pressure begins to drop quickly, until the wind suddenly increases, and then begins to rise.
Thunderstorms can be divided into local, frontal, night, and in the mountains. Most often a person encounters local or thermal thunderstorms. Water vapor in the rising flow of warm air condenses at altitude, a lot of heat is released, and the rising air flows heat up. Compared to the surrounding air, the rising air is warmer, it increases in volume until it turns into a thundercloud. Large thunderclouds contain ice crystals and water droplets. As a result of their fragmentation and friction with each other and with the air, positive and negative charges are formed, under the influence of which a strong electrostatic field arises (the electrostatic field strength can reach 100,000 V/m). And the potential difference between individual parts of the cloud, clouds or cloud and earth reaches enormous values. When the critical electrical intensity in the air is reached, an avalanche-like ionization of the air occurs - a lightning spark discharge.
A frontal thunderstorm occurs when a mass of cold air moves into an area where warm weather prevails. Cold air displaces warm air, with the latter rising to a height of 5-7 km. Warm layers of air invade into vortices of various directions, a squall is formed, strong friction between the layers of air, which contributes to the accumulation of electrical charges. The length of a frontal thunderstorm can reach 100 km. Unlike local thunderstorms, it usually gets colder after frontal thunderstorms. Night thunderstorms are associated with the cooling of the ground at night and the formation of eddy currents of descending air.
Thunderstorms in the mountains are explained by the difference in solar radiation to which the southern and northern slopes of the mountains are exposed. Night and mountain thunderstorms are persistent and short-lived. Thunderstorm activity varies in different areas of our planet. World centers of thunderstorms: Java island - 220 thunderstorm hoarfrost per year; Equatorial Africa - 150; Southern Mexico - 142; Panama 132; Central Brazil - 106. Russia: Murmansk - 5; Arkhangelsk - 10; St. Petersburg - 15; Moscow - 20. As a rule, the further south “for the northern hemisphere of the Earth” and the further north “for the southern hemisphere of the Earth”, the higher the thunderstorm activity. Thunderstorms are very rare in the Arctic and Antarctic. There are 16 million thunderstorms on Earth every year. For every m2 of earth's surface there are 2-3 lightning strikes per year. The ground is most often struck by lightning from negatively charged clouds.
Lightning is distinguished by type: linear, pearl and ball. Pearl and ball lightning are quite rare occurrences. Their characteristics: a common linear lightning, which any person encounters many times, has the appearance of a branching line. The current strength in the linear lightning channel is on average 60 - 170 kA; lightning with a current of 290 kA has been recorded. The average lightning has an energy of 0 kW/hour “900 MJ”. The discharge develops in a few thousandths of a second; at such high currents, the air in the lightning channel zone almost instantly heats up to a temperature of 30,000 - 33,000°C. As a result, pressure is sharply applied, the air expands and a shock wave appears, accompanied by a sound impulse - thunder. *Pearl lightning is a very rare and beautiful phenomenon. Appears immediately after linear lightning and disappears gradually. Most often, the discharge of pearl lightning follows the path of the repaired one. The lightning appears to be 12 m apart and resembles pearls strung on a string. Pearl Lightning can be accompanied by exceptional sound effects.
Ball lightning is also quite rare. For thousands of ordinary linear lightning, there are 2-3 ball lightning. Ball lightning, as a rule, appears more often towards the end of a thunderstorm, less often after a thunderstorm. It can have the shape of a ball, ellipsoid, pear, disk, or even a chain of balls. The color of Lightning is red, yellow, orange-red. Sometimes lightning is dazzling white with very sharp outlines. Color is determined by the content of various substances in the air. The shape and color of lightning may change during a discharge. It was not possible to measure the parameters of ball lightning and simulate it in laboratory conditions. Apparently, many observed unidentified flying objects "UFOs" are similar or similar in nature to ball lightning.
Hazardous factors of lightning: Linear lightning. Due to the fact that lightning is characterized by large values of currents, voltages and discharge temperatures, its impact on a person, as a rule, leads to their death. On average, about 3,000 people die from lightning strikes in the world every year, and there are known cases of several people being struck at the same time. A lightning discharge follows the path of least electrical resistance: if you place two masts next to each other - a metal one and a tall wooden one, then lightning will most likely strike the metal mast, although it is lower, because the electrical conductivity of the metal is higher; lightning also strikes clayey and wet areas much more often than dry and sandy ones, since the former have greater electrical conductivity; in the forest, lightning also acts selectively, hitting, first of all, deciduous trees such as oak, poplar, willow, and ash, since they contain a lot of starch. Coniferous trees - spruce, fir, larch and deciduous trees such as linden, walnut, beech - contain a lot of oils, therefore they have high electrical resistance, and lightning strikes them less often.
Out of 100 trees, lightning strikes: 27 percent of poplars; 20 percent pears; 12 percent limes; 8 percent spruce and only 0.5 percent cedar. In addition to damaging people and animals, linear lightning quite often causes forest fires, as well as residential and industrial buildings, especially in rural areas. In this regard, it is necessary to take special protection against linear lightning. Ball lightning. If the nature of linear lightning is clear, and, therefore, its behavior is predictable, then the nature of ball lightning is still not clear. The danger of a person being struck by ball lightning is, first of all, associated precisely with the lack of methods and rules for protecting people from it.
In 1753, Russian physicist Georg Wilhelm Richmann, colleague of M.V. Lomonosov, was killed by ball lightning during a thunderstorm while researching spark discharges in the atmosphere. There are many known cases of people dying when encountering ball lightning. A dramatic incident occurred with a group of five Soviet climbers on August 17, 1978 in the Caucasus at an altitude of about 4000m, where they stopped for the night on a clear, cold night. A light yellow ball the size of a tennis ball flew into the climbers’ tent. The ball hovered over the sleeping bags in which the climbers were located, and methodically, according to some plan of its own, penetrated into the sleeping bags. Each such “visit” caused a desperate inhuman cry, people felt extreme pain, as if they were being burned with an autogenous gas, and lost consciousness. They could not move their arms or legs. After the ball “visited” the sleeping bags of each climber several times, it disappeared. All climbers received many serious wounds. These were not burns, but lacerations: the muscles were torn out in whole pieces, right down to the bones. One of the climbers, Oleg Korovin, was killed by the ball. At the same time, the ball lightning did not touch a single object in the tent, but only injured people.
The behavior of ball lightning is unpredictable. She suddenly appears anywhere, including indoors. Cases of ball lightning appearing from a telephone handset, an electric razor, a switch, a socket, or a loudspeaker have been observed. It quite often enters buildings through pipes, open windows and doors. Ball lightning sizes range from several centimeters to several meters. Usually it easily floats or rolls above the ground, sometimes jumps. It reacts to wind, draft, rising and moving air currents. However, there was a case when ball lightning did not react to the air flow.
Ball lightning can appear without causing harm to a person or a room, fly through a window and disappear from the room through an open door or chimney, flying past a person. Any contact with it leads to severe injuries, burns, and in most cases, death. Wide lightning may explode. The resulting air wave can injure a person or lead to destruction in a building. There are known cases of lightning explosions in stoves and chimneys, which led to the destruction of the latter. The collected evidence on the behavior of ball myopia suggests that in most cases the explosions were not dangerous, severe consequences occurred in 10 cases out of 100. It is believed that ball lightning has a temperature of about 5000 ° C and can cause a fire.
`Rules of behavior during a thunderstorm:
We see a flash of lightning almost instantly, as light travels at a speed of 300,000 km/s. The speed of sound in air is approximately 344 m/s, that is, in about 3 seconds, sound travels 1 km. Lightning is dangerous when the flash is immediately followed by a clap of thunder, which means that a thundercloud is above you, and the danger of a lightning strike is most likely. Your actions before and during a thunderstorm should be winter-proof: leave the house, close windows, doors and chimneys, make sure that there is no draft that can attract ball lightning. During a thunderstorm, do not light the stove, since the smoke coming out of the chimney has high electrical conductivity, and the likelihood of a lightning strike into the chimney rising above the roof increases; During a thunderstorm, stay away from electrical wiring, antennas, windows, doors and everything else connected to the external environment. Do not sit near a wall next to which there is a tall tree; disconnect radios and televisions from the network, do not use electrical appliances and telephones “this is especially important for rural areas”; “and it’s time to walk and hide in the nearest building. A thunderstorm in a field is especially dangerous. When looking for shelter, give preference to a large metal structure or a structure with a metal frame, a residential building or fugue over a building protected by a lightning rod; if it is not possible to hide in a building, there is no need to hide in small sheds or under lonely trees; do not stay on hills and open unprotected places, near metal or mesh fences, large metal objects, wet walls, lightning rod grounding; in the absence of shelter, lie on the ground, and preference should be given to dry sandy soil, far from the reservoir; If a thunderstorm finds you in the forest, you need to rummage through an area with low-growing trees. You cannot take shelter under tall trees, especially pine trees, oaks, and poplars. It is better to be no more than 30 m away from a separate tall tree. Pay attention to whether there are any nearby trees that were previously damaged by a thunderstorm and split. It's better to stay away from this place. The abundance of trees struck by lightning indicates that the soil in this area has high electrical conductivity, and a lightning strike in a muddy area is very likely. During a thunderstorm, you cannot be on the water and you cannot swim or fish near the water. It is necessary to move further away from the beret, and in the mountains, move away from the mountain ridges of sharp towering skips and peaks. When a thunderstorm approaches in the mountains, you need to go as low as possible. Collect metal objects - climbing pitons, ice axes, pots - into a backpack and lower them on a rope 20-30 m down the slope; during a thunderstorm, do not engage in outdoor sports or run, as it is believed that sweat and rapid movement “attract” lightning; if you are caught in a thunderstorm on a bicycle or motorcycle, stop driving, leave them and wait out the thunderstorm at a distance of about 30 m from them; If a thunderstorm finds you in your car, you do not need to leave it. It is necessary to close the windows and lower the car antenna. It is not recommended to drive a car during a thunderstorm, since a thunderstorm is usually accompanied by rain, which impairs visibility on the road, and a flash of lightning can blind and cause fear and, as a result, an accident; When encountering ball lightning, do not show any activity towards it, if possible, remain calm and do not move. There is no need to approach her or touch her with anything, because... an explosion may occur. You should not run away from ball lightning, because this can cause it to flow with the resulting air flow.
Lightning protection:
An effective means of protection against lightning is lightning rods. The priority of the invention of the lightning rod belongs to the American Benjamin Franklin “1749”. Somewhat later, in 1758, independently of him, the lightning rod was invented by M.V. Lomonosov. Lightning protection by installing lightning rods is based on the property of lightning to strike the highest and well-grounded metal structures. The lightning rod consists of three main parts: an air terminal that receives a lightning strike; a current conductor connecting the lightning rod to the ground electrode, through which the lightning current flows into the ground. The most common types of air terminals are rod and cable. Lightning rods are divided into: single, double and multiple.
A protection zone is formed around the lightning rod, that is, a space within which a building or any other object is protected from a direct lightning strike. The degree of protection in these areas is more than 95 percent. This means that out of 100 lightning strikes, less than 5 hits are possible on a protected object; the remaining strikes will be perceived by the lightning rod. The protection zone is limited by the generatrices of two cones, one of which has a height h equal to the height of the lightning rod and a base radius R = 0.75 h, and the other has a height of 0.8 h and a base radius of 1.5 h “with the base radius of the second cone R = h protection efficiency is ensured at 99 percent.”
Lightning rod lightning rods are made of steel of any profile, usually round, with a cross-section of at least 100 mm2 and a length of at least 200 mm. To protect against corrosion, they are painted. Lightning rods of cable lightning rods are made of metal cables with a diameter of about 7 mm. Current conductors must withstand the heat of very high lightning currents flowing over a short period of time, so they are made from metals with low resistance. The cross-section of current conductors in the air should not be less than 48 mm2, and in the ground - 160 mm2. Grounding conductors are the most important element of lightning protection. Their purpose is to provide a sufficiently low resistance to the spread of lightning current in the ground. As a grounding conductor, you can use metal pipes, slabs, coils of wire and mesh, pieces of predatory reinforcement buried in the ground to a depth of 2 - 2.5 m. It is advisable to install lightning rods on hills to shorten the lightning path and increase the size of the protection zone. Chimneys, gables , roof ledges, television antennas must be grounded using current conductors. Metal drainpipes and stairs leading to the roof should preferably be connected to a current conductor or grounded separately.
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The electrical nature of lightning was revealed in the research of the American physicist B. Franklin, on whose initiative 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 in which he described an experiment using a kite launched into a thunderstorm. Franklin's experience was described in the work of Joseph Priestley.
The average length of lightning is 2.5 km, some discharges extend up to 20 km in the atmosphere.
How does lightning form? 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.
Scheme of lightning occurrence: a - formation; b - category.
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 with a strength sufficient to initiate an electrical discharge (~ 1 MV/m) is formed, and in a significant part of the cloud there is a 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 and light.
Linear lightning is usually observed, which belongs to the so-called electrodeless discharges, since they begin (and end) in accumulations of charged particles. This determines some of their 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 square kilometers.
The most studied process of lightning development in thunderclouds, while lightning can pass in the clouds themselves (intracloud lightning), or can strike the ground (ground lightning).
Development diagram of ground lightning: a, b - two leader stages; 1 - cloud; 2 - streamers; 3 - step leader channel; 4 - channel crown; 5 - pulse corona on the channel head; c - formation of the main lightning channel (K).
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 electrons, 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, the discharge is initiated by high-energy cosmic rays, which trigger a process called runaway electron breakdown. Thus, electron avalanches arise, turning into threads of electrical discharges - streamers, which are well-conducting channels, which, merging, give rise to a bright thermally ionized channel with high conductivity - a stepped lightning leader.
The movement of the leader towards the earth's surface occurs in steps of 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, followed by a stop and weakening of the glow 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 intensity at its end increases, and under its action, a response streamer is ejected from objects protruding on the surface of the Earth, connecting to the leader. This feature of lightning is used to create a lightning rod.
In the final stage, a reverse (from bottom to top), or main, lightning discharge follows along the channel ionized by the leader, characterized by currents from tens to hundreds of thousands of amperes, a brightness noticeably exceeding the brightness of the leader, and a high speed of progress, initially reaching ~ 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 25,000 °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.
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 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 emissions, the so-called atmospherics.
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.
Every second, about 50 lightning strikes the surface of the earth, and on average, every square kilometer of it is struck by lightning six times a year.
Lightning is a serious threat to human life. A person or animal being struck by lightning often occurs in open spaces, because... The electric current follows 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.
In the body of lightning victims, the same pathological changes are observed as in case of electric shock. The victim loses consciousness, falls, may experience convulsions, and often stops breathing and heartbeat. You can usually find “current marks” on the body—the places where electricity enters and exits.
These are tree-like light pink or red stripes that disappear 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. In case of death, the cause of cessation of basic vital functions is the sudden stop of breathing and heartbeat from the direct effect of lightning on the respiratory and vasomotor centers of the medulla oblongata.
If struck by lightning, first aid should be immediate. In severe cases (stopping breathing and heartbeat), resuscitation is necessary; it should be provided by any witness to the misfortune without waiting for medical workers. Resuscitation is effective only in the first minutes after a lightning strike; after 10-15 minutes it is, as a rule, no longer effective. Emergency hospitalization is necessary in all cases.
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Tall trees are frequent targets for lightning. You can easily find multiple lightning scars on long-lived relict trees. A single standing tree is thought to be more likely to be struck by lightning, although in some forested areas lightning scars can be seen on almost every tree. Dry trees catch fire when struck by lightning. Most often, lightning strikes are directed at oak, least often at beech, which apparently depends on the different amounts of fatty oils in them, which represent great resistance to electricity.
Lightning travels through 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. Tall trees planted near a building catch lightning, and the high biomass of the root system helps ground the lightning strike.
Musical instruments are made from trees struck by lightning, attributing unique properties to them.
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)
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. 
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. 
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. 
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 is a giant electrical spark discharge between clouds or between clouds and the earth's surface several kilometers long, tens of centimeters in diameter and lasting tenths of a second. Lightning is accompanied by thunder. In addition to linear lightning, ball lightning is occasionally observed.
Thunderstorm is a complex atmospheric process, and its occurrence is caused by the formation of cumulonimbus clouds. Heavy cloudiness is a consequence of significant atmospheric instability. A thunderstorm is characterized by strong winds, often intense rain (snow), sometimes with hail. Before a thunderstorm (an hour or two before a thunderstorm), atmospheric pressure begins to drop rapidly until the wind suddenly increases, and then begins to rise.
Thunderstorms can be divided into local, frontal, night, and in the mountains. Most often, a person encounters local or thermal thunderstorms. These thunderstorms occur only in hot weather with high atmospheric humidity. As a rule, they occur in the summer at midday or afternoon (12-16 hours). Water vapor in the rising flow of warm air condenses at altitude, releasing a lot of heat and heating the rising air flows. Compared to the surrounding air, the rising air is warmer and expands in volume until it becomes a thundercloud. Ice crystals and water droplets constantly hover in large thunderclouds. As a result of their fragmentation and friction with each other and with the air, positive and negative charges are formed, under the influence of which a strong electrostatic field arises (the electrostatic field strength can reach 100,000 V/m). And the potential difference between individual parts of the cloud, clouds or cloud and earth reaches enormous values. When the critical intensity of the electric air is reached, an avalanche-like ionization of the air occurs - a lightning spark discharge.
A frontal thunderstorm occurs when a mass of cold air moves into an area where warm weather prevails. Cold air displaces warm air, with the latter rising to a height of 5-7 km. Warm layers of air invade into vortices of various directions, a squall is formed, strong friction between the layers of air, which contributes to the accumulation of electrical charges. The length of a frontal thunderstorm can reach 100 km. Unlike local thunderstorms, it usually gets colder after frontal thunderstorms. Night thunderstorms are associated with the cooling of the ground at night and the formation of eddy currents of rising air. Thunderstorms in the mountains are explained by the difference in solar radiation to which the southern and northern slopes of the mountains are exposed. Night and mountain thunderstorms are weak and short-lived.
Thunderstorm activity varies in different areas of our planet. World centers of thunderstorms: Java Island - 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.
By type, lightning is divided into linear, pearl and ball. Pearl and ball lightning are quite rare occurrences.
A lightning discharge develops in a few thousandths of a second; at such high currents, the air in the zone of the lightning channel almost instantly heats up to a temperature of 30,000-33,000 ° C. As a result, the pressure rises sharply, the air expands - a shock wave appears, accompanied by a sound pulse - thunder. Due to the fact that the intensity of the electric field created by the static electric charge of the cloud is especially high on tall, pointed objects, a glow occurs; as a result, ionization of the air begins, a glow discharge occurs and reddish tongues of glow appear, at times shortening and lengthening again. You should not try to extinguish these fires because... there is no combustion. At high electric field strength, a bunch of luminous filaments may appear - a corona discharge, which is accompanied by hissing. Linear lightning can also occasionally occur in the absence of thunderclouds. It is no coincidence that the saying “bolt from the blue” arose.
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The creation of new projects involves a preliminary economic justification for their feasibility, subsequent...
Reporting is generated by the RM, is agreed upon (approved) by the Risk Committee under the Management Board and transmitted to...
At the edge of a large, very large meadow, on a long emerald blade of grass lived a tiny Ladybug. Little Ladybug...
Nowadays, it is quite common for people to turn to the stars. With the help of a horoscope a person can learn a lot about...
Business or friendly. If you were pursuing a stranger, it means your level of trust in the female sex...
according to Freud's dream book If you dreamed about how you were fishing, it means that in real life you can hardly switch off...
The New Year's whirlwind will spin us around so quickly and rapidly that it's time to thoroughly think through the New Year's...
The article offers you some of the most delicious recipes for making vinaigrette. Vinaigrette is a delicious salad...
July 4th, 2015 , 08:33 pm Lately our Nastena has been completely giving up sweets (and thank God), but...
Fragrant, very tasty chocolate cake, it’s impossible to stop eating! The Negro’s Kiss cake is very easy to prepare,...
Dream interpretation is an ancient art that allows you to at least assess the psychological status...
As soon as the first mirrors were born, people immediately endowed them with all sorts of mystical abilities....
The head of a small business can easily manage the budget independently. CHECKED! If you manage...
The creation of new projects involves a preliminary economic justification for their feasibility, subsequent...