Thunderstorm Lightning and Cosmic Line

Jia Huanyu

Institute of Modern Physics, Southwest Jiaotong University

In the afternoon of a hot summer day, the sky was densely clouded, and a thunderstorm hit the Shanghai Bund. The photo taken in Figure 1 is the lightning appearing on the pearl tower of Shanghai Oriental in this thunderstorm.

Figure 1 Lightning weather appears in Shanghai, and lightning over the Oriental Pearl

(Picture from Baidu Encyclopedia)

Thunderstorms are one of the most spectacular and important atmospheric phenomena in nature, often occur in spring and summer afternoon in tropical and temperate regions. Thunderstorms can be accompanied by lightning strikes, lightning, strong wind and heavy precipitation. Thunderstorm weather from the appearance of thunderstorms to disappearing, with strong locality and suddenness. The space levels are from several kilometers to hundreds of kilometers. How many hours.

The disaster caused by strong thunderbolic weather is one of the top ten natural disasters in the world, and it is huge destructive. The number of people in China due to the number of lightning casualties every year, and a large part of the world forest fire is caused by lightning. The affected industry involves aerospace, defense, communications, computers, power transportation, electronics industry, petrochemical, mining, railway trunk lines Many departments such as architecture.

In fact, the natural phenomenon of thunderstorms can be traced back to the early days of human civilization. Ancient Chinese, ancient Rome, and ancient American civilization are related to thunderstorms.

01

Thunderstorm and lightning

In 1752, American scientist Benjamin Franklin performed lightning experiments, that is, kite experiments, and conducted in -depth research on lightning, revealing that the lightning in the sky and the electricity generated by artificial friction had the same nature. Since then, Lightning has always received widespread attention from people, and it is an important research object of atmospheric science. With the continuous improvement and improvement of thunderstorm detection technology, scientists have carried out a lot of research, and have a deep understanding of the formation mechanism and activities of thunderstorm lightning.

Figure 2 Kite Experiment (Picture from Baidu Encyclopedia)

Thunderstorm is the shape of the heat and cooling caused by the air to the flow of the air, and the shape of the water steam saturated in the air is like a strong cloud body of the steamed bun with a flat top. When the clouds began, the charged particles in the cloud were distributed in chaos, and the clouds were both electrical on the whole. With the development of clouds, the development of electricity particles in the cloud into an orderly spatial distribution, forming positive and negative charge centers in the cloud, and the strength of the electric field generated by positive negative charge has gradually increased. At the thunderstorm stage, a strong positive and negative charge center is formed in the clouds, and the electric field becomes a strong electric field, and the power field strength can reach 80 ~ 280 kV/m.

1.1

Thunderstorm charging structure

The thunderstorm cloud has a charge, and its charge distribution structure is very complicated, which is related to meteorological and terrain conditions. The lightning clouds in different seasons and regions are not exactly the same. The charge structures in different stages of the same thunderstorms are also different. The area and the sinking flow area are also different.

At the beginning of the 20th century, Wilson and Simpson, the founders in the field of modern thunderstorms, used different detection methods to start research on the charging structure of thunderbolt clouds. Wilson's first use of electrostatic field measurements to infer the amount of charge structures in thunderstorm clouds and the amount of charge in lightning, while the cloud field explores carried out by Simpson and his colleagues provided direct scientific evidence of the thunderstorm charging structure.

Thunderbolt charging structure can be roughly divided into puppet polar structure and triggea structure, as well as multi -polar structures and anti -polar structure and tilt structures. The even polar structure refers to the vertical puppet polarity of the space charging structure of the thunderbolt cloud. The three pole charge structure proposed by Simpson and others refers to a positive charge area with a charge of 24 meters at a height of 7 kilometers and a temperature of about -20 ° C. A negative charge area with a charge of -20 Kulun with a temperature of about -7 ° C is below 2 kilometers. There is a sub-positive charge area with a charge of 4 Kulun near 2 kilometers above 2 kilometers and the temperature is higher than 0 ° C. The three poles charge structures are shown in Figure 3. Although the electric field in recent years has shown that the charging structure in thunderstorms may be much more complicated than the three pole charges structures, to this day, in many cases, the main charge areas in single thunderstorms are still commonly used in classics. The three poles charge structures are represented.

Figure 3 Diagram and lightning schematic diagram of thunderstorms (pictures from Wang Junfang Report)

1.2

Thunderstorm cloud calling mechanism

In order to explain the generation and distribution of the charges in the thunderbolt cloud, people have started the research on the mechanism of calling in the clouds very early, and proposed a variety of mechanisms. These call -up mechanisms can be divided into micro -charging or particle calls and macro -generating mechanisms. There are various scale and different phase of water -based particles (霰, hail, snowflakes, raindrops, ice crystals, etc.) in various scale and different phase. These particles are interacted to call, which is called micro -calls. In addition, there are large -scale strong rising airflows in the clouds. Considering the process of dating, transmission, ion diffusion, and turbulence diffusion in thunderstorms, different geeic charges in different parts of the clouds are generated. The results of various tests and field observations and numerical simulation tests in the laboratory believe that non -sensing mechanisms such as induction, induction, and secondary ice crystals and secondary ice crystals and ion diffusion, ionic conduct capture, and current electricity and other macro macro The mechanism of calling is an important thunderstorm calling mechanism.

The non -sensing mechanism is considered to be the most important mechanism. Studies have found that large (霰 granu or soft hail) small (ice crystal) ice -phase particles occur between collisions and bounces, and occur between two particles. The charge transfer. When the suitable temperature and liquid water content, the grains are negatively charged and the ice crystals are positive. Under the influence of flow fields and gravity, large and small particles are distributed in a macro -layered layering, which makes the thunderstorms appear upside down. The sensing mechanism is shown in Figure 4. Under the influence of the external electrical field formed by the ionizing layer, heavy raindrops and small clouds are polarized. If the electric field is vertically downward, the upper part of the raindrops and cloud droplets are polarized to negative power. The lower half of the polarization is positive. During the movement of heavy rain drops, the encounter with the upward movement in the upward movement collided, the power exchange, the cloud drip of the loose charged cloud to the upper part of the cloud, and the charged raindrops moved to the lower part of the cloud, thereby forming the upper part of the cloud and the upper part of the cloud. The charging center with a positive and lower part.

Figure 4 Diagram of the mechanism of thunderstorm cloud induction

Ion spreading refers to the difference in the landing speed and positive and negative ion migration rate in the above -mentioned induction mechanism. The process of adsorbing the water pellets of the water adsorption through the conductivity will be adsorbed.

The charging mechanism in the thunderstorm cloud, that is, the separation of positive negative charge in the cloud is more complicated to form a mechanism for formation of different polar lots. It may be a mechanism of calling, or it may be a comprehensive role of a mechanism. Under the comprehensive effect of a variety of mechanisms, it may also be one or more mechanisms, supplemented by other electrical mechanisms.

1.3

Lightning in thunderstorms

With the continuous accumulation of positive and negative charge in the thunderstorm cloud, when the intensity of local electric field strength in the cloud can break through the air (generally 2500 ~ 3000 kV per meter (KV/m)), the occurrence of lightning will be stimulated. Lightning is the discharge process between different symbols in thunderstorms. During the discharge process, the temperature in the flashway increased sharply, causing the air volume to swell sharply, which caused a shock wave and caused a strong thunder. According to Lightning, lightning can be divided into two categories: cloud and flash. As shown in Figure 3, cloud flash refers to lightning that does not have contact with the earth and ground objects, including the clouds in the clouds, lightning lightning, and cloud -empty lightning. Flash refers to the discharge process between the cloud center and the earth and the ground object.

Lightning generates a strong current, causing changes in strong electromagnetic radiation and electrostatic fields. Lightning has the characteristics of short duration (10-7 ~ 1 second), fast development speed (104 ~ 108 meters per second), and large spatial scale span (from molecular scale to rice level to tens of thousands of kilometers).

In the 1990s, people used aircraft, balloons, and satellites to find a high -energy photon radiation phenomenon that existed in thunderstorms and thunderstorms than visible photon energy in thunderstorms, such as Gamma Flash (TGF). Later, the detector on the ground and the mountain also found a high -energy photon radiation directly generated by the lightning process.

These interesting new phenomena and new progress have further aroused the interested in cross -study of disciplines such as physics, atmospheric science, space physics, and celestial physics. Among them, the relationship between the universe line and the atmospheric electric field and thunderstorm lightning is an important area for the attention of the cosmic line researchers.

02

Cosmic line

The cosmic line is a high -energy particle flow from the space of the universe, and its discovery comes from the research on the phenomenon of the earth's atmospheric power. People have found that there is a phenomenon of ionization in the air very early, and believes that this ionization is caused by ground radiation, and the stronger the radiation, the higher the air power ionization. Air power ionization can be determined with an ionization room. Beginning in 1911, the amateur of the balloon flying, Austrian physicist Hus (Figure 5) hung the ionizer under the balloon and flew away from the ground to measure the height of the air and electricity. The high altitude of rice turned the radiation intensity of the ionization of air, turned out to be 9 times the ground. Because the results of the day and night measurement are the same, Hus breaks the radiation rays that cause air ionization, but not from the sun, but from the space of the universe. Initially, this radiation was called "Hess Radiation" and was later officially named "Cosmic Radio", referred to as the cosmic line. Now we think that the cosmic line is the general name of the high -energy particle flow from the universe space, and it is an integral part of the earth's environmental background radiation. The background radiation here refers to the widely existed radiation in the earth environment of our lives. In addition to the cosmic line, it also includes surface radiation and the human body radiation.

Figure 5 The discoverer of the Universe Line Hess

The cosmic line is mainly composed of atomic nucleus such as protons and nucleus, and also contains a small amount of electron and neutral gamma rays. Although these particles may also be generated in the sun and interstellar space, it mainly comes from outside the galaxy or the galaxy. They spread in the interstellar and solar system, and finally reached the earth. The energy of the cosmic mitigation can exceed 1020 electron volt (EV, 1 electron volt equal to 1.6 × 10-19 scorched ear), far exceeding the energy (1013EV) that can be achieved by particle accelerators on the earth. From the study of the universe line, people found positive electronics, Miaozi and π meson, and created the discipline of particle physics. Cosmic line research has always been an important area of ​​celestial physics.

In the study of the universe line, we call the cosmic taunles that enter the earth's atmosphere as the original cosmic line. After entering the atmospheric atmosphere of the original universe, it collided with the atomic nucleus such as oxygen and nitrogen in the atmosphere, and transformed into a secondary cosmic tone. The transformation of first -level and first -level real estate will produce a huge particle group. This large -scale air cluster phenomenon is called the universe line wide atmospheric shot (EAS). The French Ogil first found this phenomenon when observing in the Alps in 1938. These EAS secondary particles form a particle plate to the ground at a speed of light. EAS secondary particles are mainly composed of electronics, Miaozi, Qiangzi, and unprepared photons, neutrons and neutrinos. Using a large -scale detector on the ground to record the EAS particles can study the process of interacting with the original cosmic line and the interaction of the air and air. Figure 6 Schematic diagram of the wide extension of the air cluster of the universe line (picture from Baidu picture)

03

Cosmic line and thunderstorm Lightning

With the advancement and development of human science and technology, the impact of cosmic lines on human modern communications and aerospace activities has increased. The cosmic line also has the role of the atmosphere and weather of the earth. The energy brought by the universe line can be ignored compared to the weather process energy, but the cosmic line has the ability to ionize air. Therefore, the cosmic line entering the earth environment changes due to the modulation strength of the solar activity, which may lead to the weather and climate of the earth's weather and climate. The change of changes may be the reason or part of the reason or part of the problem of the world's climate change. People have conducted many research, discussions and arguments on this major issue, and there are still great differences in it.

3.1

The association between the universe line and the atmospheric electric field

The cosmic line and the sun's ultraviolet rays and ground radiation led the atmospheric electricity to form atmosphere. Atmospheric ionization layers are in areas with a height of 50 to 1000km. Compared with the ground, a voltage of about 250 k V is maintained, forming a sunny atmospheric electric field. Near the earth on the ground, the intensity of the sunny atmosphere is about 100 ~ 200 volts per meter (V/m), pointing to the ground. The actual value of the atmospheric electric fields in various places depends on the local conditions, such as the dust, landforms, and season and time in the atmosphere. The changes in the atmospheric electric field can provide important information about weather changes and environmental changes, which is an important weather parameter. The strength of the electric field detected in thunderstorms is 80 ~ 280 kV/m, and the threshold value less than the air breakdown of the electric field is 2500 ~ 3000 kV/m, which means that a strong enough electric field can naturally stimulate lightning inside the thunderstorm cloud. The lightning starting mechanism has been concerned for a long time, but has not been fully understood and recognized.

In 1924, Wilson pointed out that the strong electric field in thunderstorms can accelerate the small electrons in the cosmic -level particles to high energy and propose the concept of "escape electronics". High -energy phenomenon has become a research hotspot in atmospheric physics. In 1992, Alex VGUREVICH et al. Proposed a new theory of lightning. It is believed that the electrons of about 1 meged electron volt (MEV, 106EV) in the universe's secondary particles can be accelerated by the thunderstorm electric field. When obtaining enough energy, the air molecular ionization will generate new electrons. Accelerated by the electric field, so that the avalanche effect caused the number of electrons to increase. Increase the number of charged particles through this theory of Electronic Elimination (RREA), thereby triggering the large -scale energy release of lightning. That is to say, the wide and extension of the cosmic line is a catalyst that causes lightning. Over the years, many scientists have tried to detect the gamma ray flashing phenomenon (TGFS) through satellite experiments, and observe experiments through the ground cosmic line to find the sudden enhancement of the ground -level particles of the ground cosmic in the thunderstorm (TGES), and then explore the thunderstorms. The electric field accelerates the high -energy particles generated by the universe line. As shown in Figure 7.

Figure 7 Lightning Lightning and Cosmic Line EAS Secondary particle contact diagram

Although it is currently convinced that the reason for lightning is that some kind of escape collapse, there are certain indirect evidence that this escape collapse may be caused by the cosmic line above the clouds, but it is not certain that the escape collapse is caused by the cosmic line. Direct measurement and analysis of the connection between the intensity of the universe line and the changes in the thunderstorm atmosphere is essential. On the other hand, the influence of the atmospheric electric field in thunderstorms on the development of the cosmic line air cluster is also a special concern in the study of the physical ground observation of the cosmic line. Research between the universe line and the atmospheric electric field can also provide important information about the interaction between cosmic meals and atmosphere and spreading in the atmosphere.

In short, the association between the cosmic line and the atmospheric electric field, especially the period of strong changes in the cosmic line, and the relationship between the two during the thunderstorm period is an important, theoretical and practical cross -disciplinary issue.

3.2

Research Progress of Cosmic Line and Thunderstorm Lightning Research Progress

Atmospheric electric fields, especially thunderous cloud atmosphere, can accelerate or reduce the EAS secondary particles to change the size of the EAS case. Therefore, the counting of the cosmic line of ground detection will change with the atmospheric electric field. On the other hand, EAS secondary particles will also radiate new and more secondary particles in thunderstorms, which may trigger lightning. Lightning must form a conductive channel that penetrate the cloud layer. People are still unclear. The large -scale diffusion discharge caused by the escape collapse caused by the cosmic line is to form such a narrow high temperature channel. This has also become the focus and hotspot of various research groups in the world. For the first time in 1985, Alexeyenko and others discovered the sub -cosmic line intensity changes during the thunderstorm during the thunderstorm. The EAS-TOP experiment also recorded the change of the EAS count of 10%to 15%during the thunderstorm, and interpreted this change as the acceleration result of the strong electric field on the EAS secondary particles; It is understood that the escape electron in the strong electric field has occurred; the simulation of the atmosphere of the atmosphere on the universe's secondary particles is calculated, and it is found that when the electric field is greater than a certain threshold, the escape electronic crash may occur. Chinese researchers began to build a cosmic line observation station in Yangbajing, Tibet as early as the late 1980s, and study the basic problems in cosmic line physics such as the origin of the cosmic line.

The Tibetan Yangbajing Cosmic Line Observation Station on the Low latitude of the earth is a world -renowned cosmic line observation station. The observation of the cosmic line has a unique geographical advantage and can well monitor the changes in the strength of the cosmic line. Among them, the ARGO-YBJ experiment of China-Italy cooperation, as a large area of ​​the world covered with ground EAS observation experiments, has accumulated a lot of cosmic line data and some atmospheric electric field data. Using these data, scientists have also carried out research on cross -scientific cross -scientific cross -scientific research on cosmic lines.

Figure 8 Tibetan Yangbajing Cosmic Line Observation Station

On the left is the Sino -Japanese cooperation ASγ experiment, the right hall is the ARGO experiment for China -Italian cooperation

From August 2008, the Shixiu Book Team began to record the measurement of thunderstorms, sunny atmospheric electric fields and lightning in the Yangbajing Cosmic Line Observation Station. ；羊八井地区闪电活动发生在5~9月份，闪电个数7、8月份最多，闪电大多发生在一天的午后至半夜，17:00~19:00 闪电最多，地闪峰值滞后一些；正The ground flash is very small, and the negative flashes occur mainly during the scattering stage of thunderstorm cloud. The positive flash here refers to the ground flash formed by the positive charge in the cloud to the ground. Discharge; Yangbajing Cosmic Line Observation Station The cosmic line counting recorded by the sub -pile detector in the middle of the cosmic line has changed significantly during thunderstorms.

During the thunderbolt of 2011 and the summer of 2012 and 2012, the Southwest Jiaotong University Cosmic Line Research Group studied the changes in the EAS secondary particle counting rate measured by the Argo-YBJ experiment measurement station of the Yangbajing Cosmic Line of Tibet. The results showed that during the thunderstorm, the atmospheric field changed drastically, and the counting of the secondary particles of the universe line was also significantly changed. In order to understand the experimental phenomenon observed, the interaction and dissemination of the universe telle in the air have been computated with all Monte Carlo simulation. The simulation calculation results reasonably explain the above observation phenomenon.

04

Summarize

In short, the connection between the universe line and thunderbolt lightning is an important, theoretical and practical cutting -edge cutting -edge cross -edge interdisciplinary field.

The high -altitude cosmic line observation station (LHAASO) (4400 meters above sea level) is a major national scientific and technological infrastructure in Daocheng, Sichuan, China. A kilometer -flickering body plus the underground Miaozi detector (KM2A), 90,000 square meters of Shui Chellenkov detector array (WCDA), and 18 wide -angle atmosphere Chellenkov telescope (WFCTA). The experimental renderings are like Figure 9 shown. In 2021, the installation of all experiments was completed and fully operated, and Figure 10 was overlooking the photo of LHAASO experiments.

Figure 9 LHAASO experimental renderings

Figure 10 high altitude cosmic line observation station (LHAASO)

In 2021, LHAASO, which was running while building, achieved major scientific research results, and found the first batch of "PEV, 1015EV accelerators" and the highest energy photon to open the era of "ultra -high energy gams of celestial literature". This also fully demonstrates the advancedness of Lhaaso and the sensitivity of experiments, as well as the advantages such as the low thresholds, large effective area, large field of view, and all -weather. In the LHAASO experimental station, there are also cloud meter, atmospheric electric field instruments, lightning optical observations and radio frequency three -dimensional imagingers, etc., and observe thunderstorm lightning through multiple means to explore the characteristics and mechanisms of plateau lightning and thunderstorm charges, and high altitude universe universe The line observation station (LHAASO) combines the composite observation of the high -energy cosmic mitigation to conduct a detailed study of the cosmic line high -energy particles related to the thunderstorm lightning process, which is expected to make breakthrough progress.

This article is selected from "Modern Physical Knowledge" 2022 The 2nd YWA editor reprinted content only represents the author's point of view

Does not represent the position of the Institute of Physics of the Chinese Academy of Sciences

If you need to reprint, please contact the original public account

Source: Modern Physical Knowledge Magazine

Edit: Cloud Kaiye

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