How does lightning occur? How lightning is generated

Types of lightning and their hazards: Lightning is a natural phenomenon of great grandeur. During the formation of thunder and lightning, some clouds have a positive charge and others have a negative charge, and their electrostatic induction on the earth causes the ground to produce a heterosexual charge.

When the charges of these clouds accumulate to a certain extent, the electric field strength between the clouds of different charges or between the clouds and the earth can penetrate the air (generally 25-35 kV cm) and start discharging. We call this free discharge as"Pilot discharge"When it reaches the ground (buildings above the ground, overhead power lines, etc.), it will produce an inverse main discharge from the ground to the cloud. It is not advisable to enter sheds, sentry boxes and other buildings without lightning protection facilities.

Thunder and lightning is a majestic and somewhat intimidating electrical discharge phenomenon accompanied by lightning and thunder. The condition for the generation of thunder and lightning is that there is accumulation in the thunderstorm cloud and polarity is formed.

According to different topographic and meteorological conditions, lightning can generally be divided into three categories: hot lightning, frontal lightning (hot front lightning and cold front lightning), and terrain lightning.

Water vapor in the atmosphere is an internal cause of the formation of thunderclouds; The formation of thunderclouds is also related to the topography of nature as well as meteorological conditions.

Thermal lightning is a type of thunder that often occurs in the afternoon in summer, often accompanied by heavy rain or hail. Thermal lightning forms quickly and does not last long, 1 2 hours; The length of the minefield does not exceed 200,300 km, and the width does not exceed a few tens of km. The following conditions must be met for the formation of thermal lightning.

The air is very humid and the water vapor in the air is nearly saturated, which is a necessary factor for the formation of thermal lightning.

In a sunny summer, when the sun is scorching, the ground is exposed to the sun for a long time, and the temperature of the moist air near the ground rises rapidly, and people feel stuffy, which is necessary for the formation of thermal lightning.

There is no wind or light wind, resulting in uneven air humidity and temperature. The absence of wind or light winds may be due to the fact that the airflow does not change much, or it may be due to the topography (e.g., in the mountain basin).

Artificial rain itself does not cause thunder, and thunder and lightning are produced only by the friction and collision of clouds. The substances that act as rainfall bombs are usually a mixture of AGI and dry ice, or other substances that are easy to decompose and sublimate. Artificial rainfall is based on the sublimation of rainfall substances to absorb heat, so that the air temperature in the clouds drops, so that the air saturation is reduced, and the water vapor in the air quickly condenses to form raindrops with AGI as the core point of water droplets, so there is no sound.

The air in the lightning path suddenly and violently heats up, making its temperature as high as 15,000-20,000, thus causing the air to expand dramatically, and the air pressure near the channel can increase to more than 100 atmospheres. This is followed by rapid cooling, the air shrinks rapidly, and the pressure decreases. This sudden expansion and contraction occurs in a short period of a few thousandths of a second, so in the moment of the lightning explosion, a shock wave is generated.

The shock wave travels in all directions at a speed of 5,000 meters per second, and during propagation, its energy quickly decays, while the wavelength gradually increases. Seconds after the lightning strikes, the shock wave evolves into a sound wave, which is what we hear as thunder.

In summer, the sun shoots a large stream of gas particles into the earth, heating the earth, air and water vapor, so that the air and water vapor carry enough gas molecules. When the gas particles escape with air and water vapor to the edge of the universe in the opposite direction of the earth's core, they fall behind due to the weight of the large water droplets, and at the same time, the rising gas beads compete with the core of the large water droplets for part of the gas particles, so that the large water droplets have cavitation force, that is, positive electricity. The lighter water droplets have more gas force, that is, negative electricity.

In this way, the upper layer of small water beads and clouds are negatively charged due to the more air force, and the low-altitude large water bead clouds are positively charged due to the more cavitary force, and when they are combined, the phenomenon of thunder and lightning in the air is produced.

If the heat on the earth's surface is greater and the pressure of gas particles is higher, when the gas particles escape with water vapor, the gas flow formed will also compete for part of the gas particles in the earth's core, so that the earth's core will form a cavitary force and become positively electric. At this time, all clouds have a negative potential towards the ground. In this case, the lightning phenomenon is more intense, and there is often a ground discharge, resulting in low-altitude lightning phenomenon, which causes harm to human beings.

When the gas flow escapes with water vapor, it competes for the gas particles of the large water droplets and the earth's core, and the combination of the cavity force and the gas force produces the phenomenon of thunder and lightning.

In simple terms, it is the physical effect of air breakdown caused by the strong potential difference between the positive and negatively charged clouds when they approach.

The upper part of the cloud is dominated by a positive charge, and the lower part is dominated by a negative charge. As a result, a potential difference is formed between the upper and lower parts of the cloud. When the potential difference reaches a certain level, an electric discharge is generated, which leads to the formation of lightning.