Solar flare –explosive process of releasing energy (kinetic, light and heat) into upper layers Sun.

Flares cover all layers of the solar atmosphere: the photosphere, chromosphere and corona. Let us immediately note that solar flares and coronal mass ejections are different and independent manifestations solar activity.

Solar flares, as a rule, occur in places where sunspots of opposite magnetic polarity interact, or more precisely near the neutral magnetic field line separating the regions of northern and southern polarity. The energy release of a powerful solar flare can reach 6 × 10 25 J, which is 160 billion megatons of TNT or the approximate amount of global electricity consumption over 1 million years.

Animation showing two solar flares (X2.2, X9.3) that occurred on September 6, 2017. Credit: SDO

Flares are the largest explosive events in the Solar System. They are visible as bright areas on the Sun and can last from a few minutes to several hours. Photons from the flare reach Earth approximately 8.5 minutes after it begins; Then, within a few tens of minutes, powerful streams of charged particles arrive, and plasma clouds reach our planet only after two or three days.

Solar flare intensity

Flash energy determined in the visible range electromagnetic waves by the product of the glow area in the hydrogen emission line, which characterizes the heating of the lower chromosphere, and the brightness of this glow, associated with the power of the source.

A classification based on continuous homogeneous measurements of the amplitude of thermal X-ray bursts in the energy range 0.5-10 keV (with a wavelength of 0.5-8 angstroms) carried out by some artificial Earth satellites is also used.

According to the classification that was proposed in 1970 by D. Baker, a solar flare is assigned a score - a designation made from a Latin letter and an index behind it. The letter can be A, B, C, M or X depending on the magnitude of the X-ray intensity peak.

Solar flares online

The choice for classifying X-ray flares is due to a more accurate fixation of the process: if in the optical range even the largest flares increase radiation by a fraction of a percent, then in the region of soft X-ray radiation (1 nanometer) - by several orders of magnitude, and hard X-ray radiation is not created by the quiet Sun at all and is formed exclusively during outbreaks.

The Solar Dynamics Observatory captured a solar flare (X8.2) on September 10, 2017. The image shows a combination of ultraviolet light wavelengths that is extremely hot material in flashes. Credits: NASA/SDO/Goddard

Registration of X-ray radiation from the Sun, since it is completely absorbed by the Earth's atmosphere, began with the first launch spacecraft Sputnik 2, therefore, data on the intensity of X-ray radiation from solar flares before 1957 are completely absent.

Dangerous or not? Impact of solar flares

Solar flares are of practical importance in studying the elemental composition of the surface of a celestial body with a rarefied atmosphere or in its absence, acting as a source of X-ray radiation for X-ray fluorescence spectrometers installed on board spacecraft.

Hard ultraviolet and X-ray radiation from flares is the main factor responsible for the formation of the ionosphere, which can also significantly change the properties of the Earth's upper atmosphere: its density increases significantly, which leads to a rapid decrease in the altitude of the orbit of artificial satellites (up to 1 kilometer per day).

Plasma clouds ejected during flares give rise to geo magnetic storms, which in a certain way influence technology and people’s well-being. The branch of biophysics that studies the influence of changes in the activity of the Sun and the disturbances of the Earth's magnetosphere caused by it on organisms is called heliobiology. Flares also create aurora, most often near the poles.

Geomagnetic storms

Geomagnetic storm – disturbance of the geomagnetic field lasting from several hours to several days.

Geomagnetic storms are one of the types of geomagnetic activity. They are caused by the entry of disturbed solar wind streams into the Earth's vicinity and their interaction with the Earth's magnetosphere.

The frequency of occurrence of moderate and severe storms on Earth has a clear correlation with the 11-year cycle of solar activity: when medium frequency about 30 storms per year; their number can be 1-2 storms per year near the solar minimum and reach 50 storms per year near the solar maximum.

Classification of magnetic storms

K-index – is the deviation of the Earth's magnetic field from normal over a three-hour interval. The index was introduced by Julius Bartels in 1938 and represents values ​​from 0 to 9 for each three-hour interval (00:00 - 03:00, 03:00 - 06:00, 06:00 - 09:00, etc.) world time.

Kp-index – this is the planetary index. It is calculated as the average value of K-indices determined at 13 geomagnetic observatories located between 44 and 60 degrees northern and southern geomagnetic latitudes. Its range is also from 0 to 9.

G-index – five-point scale of magnetic storm strength, which was introduced by the US National Oceanic and Atmospheric Administration (NOAA) in November 1999. The G-index characterizes the intensity of a geomagnetic storm based on the impact of variations in the Earth's magnetic field on people, animals, electrical engineering, communications, navigation, etc. On this scale, magnetic storms are divided into levels from G1 (weak storms) to G5 (extremely strong storms). G-index corresponds to Kp minus 4; that is, G1 corresponds to Kp=5, G2 corresponds to Kp=6, etc.

Magnetic storms online. Magnetic storm forecast

The role of stellar flares in the origin of life

Oddly enough, scientists believe that. Powerful solar explosions may have played a decisive role in heating the Earth. The released energy transformed simple molecules into complex ones, such as DNA and RNA, necessary for life.

About 4 billion years ago, the Earth received only 70% of the energy from the Sun compared to what we have today. This means that our planet must have been. Instead, geological evidence suggests that it was warm and had oceans of liquid water. Scientists call this the "Faint Young Sun Paradox."

The Sun still produces flares and mass ejections, but they are not as frequent or intense as before. Moreover, today, which saves us from most of the energy reaching our planet. But our young planet had a weaker magnetic field. Scientists' calculations show that at that time, space weather particles traveled down magnetic field lines, crashing into the abundance of nitrogen molecules in the atmosphere, changing chemistry and creating the conditions for life.

At the same time, too a large number of energy can be detrimental to young planets. , if the magnetosphere is too weak. Understanding these processes will help scientists determine which stars and which planets may be hospitable to life.

On September 1, 1859, two English astronomers - Richard Carrington and S. Hodgson, independently observing the Sun in white light, saw something like lightning flash suddenly among one group of sunspots. This was the first observation of a new, still unknown phenomenon on the Sun; it later received the name solar flare.

What is a solar flare? In short, this is a powerful explosion on the Sun, as a result of which a colossal amount of energy accumulated in a limited volume of the solar atmosphere is quickly released.

Most often, outbreaks occur in neutral areas located between large spots of opposite polarity. Typically, the development of a flash begins with a sudden increase in brightness flare pad- areas of a brighter, and therefore hotter, photosphere. Then a catastrophic explosion occurs, during which the solar plasma heats up to 40-100 million K. This is manifested in a multiple increase in the short-wave radiation of the Sun (ultraviolet and x-rays), as well as in an increase in the “radio voice” of the daylight and in the emission of accelerated solar corpuscles (particles) . And some of the most powerful flares even generate solar cosmic rays, the protons of which reach a speed equal to half the speed of light. Such particles have deadly energy. They are capable of almost unhindered penetration into a spacecraft and destroy the cells of a living organism. Therefore, solar cosmic rays can pose a serious danger to the crew caught during a flight by a sudden flash.

Thus, solar flares emit radiation in the form of electromagnetic waves and in the form of particles of matter. The amplification of electromagnetic radiation occurs in wide range wavelengths - from hard X-rays and gamma rays to kilometer-long radio waves. In this case, the total flux of visible radiation always remains constant to within a fraction of a percent. . Weak flares on the Sun almost always occur, and large ones occur once every few months. But during the years of maximum solar activity, large solar flares occur several times a month. Typically a small flash lasts 5 to 10 minutes; the most powerful - several hours. During this time, a cloud of plasma weighing up to 10 billion tons is ejected into the near-solar space and energy is released equivalent to the explosion of tens or even hundreds of millions of hydrogen bombs! However, the power of even the largest flares does not exceed hundredths of a percent of the power of the total radiation of the Sun. Therefore, during a flare there is no noticeable increase in the luminosity of our daylight.

During the flight of the first crew on the American orbital station Skylab (May-June 1973), it was possible to photograph a flash in the light of iron vapor at a temperature of 17 million K, which should be hotter than in the center of a solar thermonuclear reactor. And in last years Pulses of gamma radiation were recorded from several flares.

Such impulses probably owe their origin to annihilation of electron-positron pairs. The positron, as is known, is the antiparticle of the electron. It has the same mass as an electron, but is endowed with the opposite electrical charge. When an electron and a positron collide, as can happen in solar flares, they are immediately destroyed, turning into two photons of gamma rays.

Like any heated body, the Sun continuously emits radio waves. Thermal radio emission from the quiet Sun, when there are no spots or flares on it, constantly emanates from the chromosphere at millimeter and centimeter waves, and from the corona at meter waves. But as soon as large spots appear, a flare occurs, strong radio bursts appear against the background of calm radio emission... And then the radio emission of the Sun increases abruptly by thousands, or even millions of times!

The physical processes leading to solar flares are very complex and still poorly understood. However, the very fact that solar flares appear almost exclusively in large groups of sunspots indicates that flares are related to strong magnetic fields on the Sun. And the flare is, apparently, nothing more than a colossal explosion caused by the sudden compression of solar plasma under the pressure of a strong magnetic field. It is the energy of magnetic fields, somehow released, that gives rise to a solar flare.
Radiation from solar flares often reaches our planet, having a strong impact on the upper layers of the earth's atmosphere (ionosphere). They also lead to the occurrence of magnetic storms and auroras.

Consequences of solar flares

On February 23, 1956, the Sun Service stations noted a powerful flare on the daylight. In an explosion of unprecedented force, giant clouds of hot plasma were thrown into the circumsolar space - each many times larger. more than Earth! And at a speed of more than 1000 km/s they rushed towards our planet. The first echoes of this catastrophe quickly reached us across the cosmic abyss. Approximately 8.5 minutes after the outbreak began, the greatly increased flux of ultraviolet and X-rays reached upper layers the earth's atmosphere - the ionosphere, increased its heating and ionization. This led to a sharp deterioration and even temporary cessation of radio communications on short waves, because instead of being reflected from the ionosphere, as from a screen, they began to be intensively absorbed by it...

Sometimes, with very strong flares, radio interference lasts for several days in a row, until the restless star “returns to normal.” The dependence can be traced here so clearly that the level of solar activity can be judged by the frequency of such interference. But the main disturbances caused on Earth by the flare activity of the star are ahead.

Following short-wave radiation (ultraviolet and x-rays), a stream of high-energy solar cosmic rays reaches our planet. True, the magnetic shell of the Earth quite reliably protects us from these deadly rays. But for astronauts working in outer space, they pose a very serious danger: exposure to radiation can easily exceed the permissible dose. That is why about 40 observatories around the world constantly participate in the Sun Patrol Service - they conduct continuous observations of the flare activity of the daylight.

Further development of geophysical phenomena on Earth can be expected a day or two days after the outbreak. This is exactly the time - 30-50 hours - required for the plasma clouds to reach the earth's "surroundings". After all, a solar flare is something like space gun, shooting into interplanetary space corpuscles - particles of solar matter: electrons, protons (nuclei of hydrogen atoms), alpha particles (nuclei of helium atoms). The mass of corpuscles erupted by the flare in February 1956 amounted to billions of tons!

As soon as the clouds of solar particles collided with the Earth, compass needles began to sweep, and the night sky above the planet was decorated with multi-colored flashes of the aurora. Heart attacks have increased sharply among patients, and the number of road accidents has increased.

What about magnetic storms, auroras... Under the pressure of gigantic corpuscular clouds, literally the entire globe shook: earthquakes occurred in many seismic zones. And as if to top it all off, the length of the day abruptly changed by as much as 10... microseconds!

Space research has shown that the globe is surrounded by a magnetosphere, that is, a magnetic shell; inside the magnetosphere, the strength of the Earth's magnetic field prevails over the strength of the interplanetary field. And in order for a flare to have an impact on the Earth’s magnetosphere and the Earth itself, it must occur at a time when the active region on the Sun is located near the center of the solar disk, that is, oriented towards our planet. Otherwise, all flare radiation (electromagnetic and corpuscular) will fly by.

The plasma that rushes from the surface of the Sun into outer space has a certain density and is capable of exerting pressure on any obstacles encountered along its path. Such a significant obstacle is the Earth's magnetic field - its magnetosphere. It counteracts the flow of solar matter. There comes a moment when in this confrontation both pressures are balanced. Then the boundary of the Earth's magnetosphere, pressed by the flow of solar plasma from the day side, is established at a distance of approximately 10 Earth radii from the surface of our planet, and the plasma, unable to move straight, begins to flow around the magnetosphere. In this case, particles of solar matter stretch its magnetic field lines, and on the night side of the Earth (in the direction opposite from the Sun) a long trail (tail) is formed near the magnetosphere, which extends beyond the orbit of the Moon. The earth with its magnetic shell finds itself inside this corpuscular flow. And if the ordinary solar wind, constantly flowing around the magnetosphere, can be compared to a light breeze, then the rapid flow of corpuscles generated by a powerful solar flare is like a terrible hurricane. When such a hurricane hits a magnetic shell globe, it contracts even more strongly on the subsolar side and plays out on Earth magnetic storm.

Thus, solar activity affects terrestrial magnetism. As it intensifies, the frequency and intensity of magnetic storms increases. But this connection is quite complex and consists of a whole chain of physical interactions. Main link This process involves an enhanced flow of corpuscles that occurs during solar flares.

Some energetic corpuscles in polar latitudes break out of a magnetic trap into the earth's atmosphere. And then, at altitudes from 100 to 1000 km, fast protons and electrons, colliding with air particles, excite them and make them glow. As a result, there is Polar Lights.

Periodic “revivals” of the great luminary are a natural phenomenon. For example, after a grandiose solar flare observed on March 6, 1989, corpuscular flows excited literally the entire magnetosphere of our planet. As a result, a strong magnetic storm broke out on Earth. It was accompanied by an aurora of astonishing scope, which reached the tropical zone in the area of ​​the California Peninsula! Three days later, a new powerful outbreak occurred, and on the night of March 13-14, residents of the southern coast of Crimea also admired the enchanting flashes spread out in the starry sky above the rocky teeth of Ai-Petri. It was a unique sight, like the glow of a fire that immediately engulfed half the sky.

The brightest star of our system, despite its relatively calm vital activity, still excites scientists. From time to time, storms and flares are observed on the Sun, as a result of which huge amounts of energy are released. Astronomers have been observing solar activity for several decades, but these processes still remain a mystery to them.

What is a solar flare?

Being the brightest, and therefore the hottest star, the Sun, its surface is subject to various cosmic phenomena. Spots, solar flares may appear on it, and storms may dominate. But a solar flare is a rather interesting and unusual phenomenon. This is a very strong process, as a result of which a huge amount of different types energy: thermal, light, and also kinetic. All this energy bursts out during a flare, the solar plasma heats up, and the speed of its emission can reach the speed of light.

Naturally, all these processes are reflected on Earth. A solar flare rarely goes unnoticed, affecting both the atmospheres of other planets and the atmosphere of Earth.

Types of flares

Scientists have identified five classes of this solar activity: A, B, C, M and X. Depending on the class, the amount of energy released and the speed, these categories are assigned a corresponding numerical value. For example, the most powerful solar flare was recorded by astronomers in November 2003. She was assigned class X28. During this process, sensors on one of NASA's satellites were damaged.

During an X-class flare, our planet may experience interference in radio signals and satellite broadcasts. In addition, magnetic storms may continue for several days.

During M-class flares, weak magnetic storms are observed, as well as interruptions in signals, mainly in polar regions. All other flares do not cause significant harm to our planet and are noticeable only in the Earth's atmosphere.

Causes

Scientists have been speculating for quite some time about why a solar flare occurs. The thing is that spots appear and disappear on the surface of the star. They have different magnetic polarities, so when the spots come into contact with each other or begin to interact in some way, magnetic flares in the sun.

The strength of such phenomena is determined by the area of ​​the glow, and it, in turn, is clearly visible on a special spectroscopic telescope. It is this device that monitors solar activity in general, and storms and flares in particular.

The Power of the Sun

Solar activity has been observed for about 40 years. During all this time, approximately 35 flares of category X7 and higher occurred. In total, over 11 years of the solar circle of activity, a little more than 37 thousand flares are observed.

Scientists have recorded the most powerful flares on the Sun. One of these occurred in 1859, later called the “great magnetic storm.” During this period, very bright light was observed on Earth. northern lights, in almost all corners. In addition, telegraph instruments failed and communications were disrupted.

The earliest strong flare is considered to be the so-called “super flare” that occurred in 774. Scientists have been analyzing and tracking for a long time solar system before coming to such conclusions. After this flare, it is believed that the Earth was exposed to radioactive and UV waves that traveled fast enough to enter the earth's atmosphere and cause damage.

IN Lately a powerful outbreak was recorded in November 2003, but its activity did not have a detrimental effect on equipment or people’s health.

Consequences of outbreaks

Weak solar activity does not bring virtually any significant changes to planet Earth. Most often, solar emissions simply do not reach our atmosphere. But if the release is quite strong, it can be dangerous. Flares have a particularly strong impact on the safety of those in orbit at the time. Satellite communications may also change or be interrupted.

In addition, solar activity can provoke magnetic storms. Solar flares create powerful plasma emissions that reach our planet in about 2-3 days, come into contact with the atmosphere and ionosphere of the Earth, as a result of which magnetic storms are formed. This phenomenon is quite safe, although it can affect the well-being of weather-dependent people.

In such people, magnetic storms cause increased pressure, resulting in headaches. A person feels weak and broken, but after a while this weakness passes.

How to improve your well-being?

Since approximately half of the population of our planet is exposed to geomagnetic storms, doctors have developed recommendations that allow you to survive the “stormy days” relatively calmly.

1. If you are weather sensitive, be aware of the possibility of magnetic storms every day so you can be prepared for them.
2. Keep the necessary medications near you. For hypertensive patients - lowering blood pressure, for hypotensive patients - increasing blood pressure. Those who suffer from headaches should stock up on migraine medications.
3. Accept different water treatments- contrast shower, swimming. This will strengthen your circulatory system and reduce the risk of worsening your condition. On magnetic days it is recommended to take a bath with sea ​​salt and essential oils.
4. On the eve of geomagnetic storms, avoid eating high-calorie foods, excessive consumption of coffee, spicy and salty foods, and generally overeating.
5. It is not advisable to be overly nervous on such days. Stock up on positive emotions.
6. If you suffer from headaches, learn acupressure techniques. It will be useful not only on days of sunny activity, but also whenever a migraine bothers you.
7. On days of magnetic storms, an ordinary refrigerator magnet will help. Just run it over your body and head, and you will improve your health by changing the charge of your blood cells.

Study of solar activity

To prevent the deterioration of the population's condition, warn about possible failures of satellite signals and other negative consequences solar flares, astronomers study the activity of the star. After all, if talk about how solar processes affect human well-being remains just talk, then the influence of these processes on the operation of various devices has been scientifically proven.

As a result of the studies, the so-called 11-year solar cycle was discovered. As a result of this teaching, it was proven that the activity of the star can be repeated every eleven years. In addition, these processes can be influenced by different planets in the solar system.

Before the first telescopes appeared, solar activity was also studied. But the study was based on observation of the star and auroras with the naked eye. It has been proven that these phenomena are directly related to the processes occurring on the Sun.

At the present time, it has also been proven that solar activity significantly affects weather conditions throughout the planet: warming or cooling, tides, changes in the level of rivers and lakes, the occurrence of atmospheric fronts, the number of thunderstorms and the amount of precipitation.

Some studies show that changes in the number of insects or some animals, as well as fluctuations in human vital signs, directly depend on the activity of the Sun. But all these hypotheses are under study.

As a result of studying processes on the Sun, everything that happens on the surface of the star is recorded. A photo of a solar flare helps to examine in more detail the force of the explosion and the speed of the plasma.

Instead of an epilogue

As you can see, solar activity partially concerns the life and health of every living creature, normal operation technical systems. That is why such a phenomenon as a solar flare is studied at space centers and observatories. A solar explosion, as some scientists call it, does not pose a clear threat to Earth. At least for the next few billion years, after which a powerful flare may occur and the star will cease to exist.

On September 6 at 15:02 (Moscow time), the largest solar flare in the last 12 years was recorded. The most powerful release of energy occurred during a period of minimal solar activity, which amazed astronomers. How such events affect the Earth is in the Futurist material.

The largest solar flare in the last 12 years was recorded by the SDO Solar Dynamics Observatory in active region 2673. The explosion with a power of X9.3 (the letter indicates the class of extremely large flares, and the number indicates its strength) occurred as a result of the interaction of two largest groups in several years sunspots. Judging by the radio emission, there was an ejection of matter from the corona - the outer layers of the Sun's atmosphere. The flare followed a weaker one (X2.2), which appeared in this area at 12:10 Moscow time, and on September 4 a series of class M flares, the previous most powerful, occurred.

As the Laboratory of Solar X-ray Astronomy of the Lebedev Physical Institute writes, this is one of the most powerful explosions that our star is capable of producing. Over 20 years of observations of the Sun, only five flares of greater intensity have been recorded (the last with a power of X17.0 was recorded in November 2005). The largest of them occurred in November 2003, its capacity was X28.

As a rule, such events occur at the peak of solar activity, but this flare appeared against the background of solar minimum - and this is its uniqueness. The flare activity after the explosion was 10.3, which corresponds to highest level. Scientists continue to figure out what caused such a large explosion during the “calm” period and predict the consequences for the Earth and outer space. The flare was observed only by foreign space observatories. The only Russian solar project (the ROC Arka space observatory) is scheduled only for 2024.

What is a solar flare?

This is a powerful explosion on the Sun, as a result of which a colossal amount of energy accumulated in the star’s atmosphere is quickly released. It is caused by reconnection of magnetic field lines in solar plasma. Typically, flashes occur in neutral areas located between dark spots of opposite polarity. Major solar flares most often occur during the period of maximum activity in the 11-year cycle. The last maximum of the current solar cycle was in April 2014. Powerful flashes may be accompanied by the ejection of matter from the solar corona.

How will this solar flare affect Earth?

According to data from space coronagraphs (instruments that monitor the solar corona and plasma flows in it), a large ejection of solar matter has occurred, and it is directed towards the Earth. The Laboratory of X-ray Astronomy of the Sun suggests that clouds of plasma (usually they are 100 million kilometers near the Earth's orbit and move at a speed of 1000 km/s) will approach the Earth on September 8 and hit its magnetic field. The arrival time of solar matter is still being calculated. The exact strength of the effects is not yet clear: it depends on the direction of the magnetic field in the cloud. If upon impact it coincides with the earth’s, the consequences will be minimal: solar plasma does not break through. If the magnetic fields are multidirectional, the plasma will break through the magnetic shield and rush into the Earth’s magnetosphere - and then auroras will bloom across the entire planet from the equator to the poles and a strong magnetic storm will rage. Determining the direction of magnetic fields is a daunting task.

Due to the action of the flow of charged particles, the upper layers of the Earth's atmosphere are heated. Along with intense radio emissions, this impairs the accuracy of navigation systems and leads to disruption of satellites, radio communications and telecommunications equipment. Satellites in high orbits are especially affected: either the vehicle becomes highly charged during a storm and its parts fail, or its components are bombarded by charged particles. But it is impossible to predict which specific satellite will die.

So far, observatories around the world are predicting a magnetic storm in the next three days with a strength of 1-2 on a 5-point scale, which will last at least 24 hours. Scientists note sudden changes Earth's magnetic field.

What other problems could there be?

Power outages over large areas. The most famous case occurred in 1989 in Quebec. Powerful currents in the magnetosphere cause excessive high voltage in power lines and damage electrical transformers and power plants. This most often occurs closer to the Earth's poles, where induced currents are greatest and in regions with long power lines and where the ground conducts poorly.

Is it true that solar flares cause headaches and spoil your mood?

Yes, this can happen. On the Earth's surface, we are well protected from the effects of charged particles and X-rays from the Sun by the Earth's magnetic field and atmosphere. The small number of very high energy particles that reach the surface does not significantly increase the levels of radiation we experience every day. Warming of the atmosphere can lead to changes atmospheric pressure, which may affect weather-sensitive people. There are claims about the influence of magnetic storms on human health, but there is no convincing evidence. Basically, the discussion of the harm of geomagnetic storms takes place in the Russian environment, while abroad it is discussed, but not postulated.

Astronauts on the ISS do not suffer from radiation, since the station is in a fairly low orbit. But a solar flare could be dangerous for those flying to the Moon or Mars.

Do pacemakers break?

Pacemakers can detect the effects of strong solar storms, but these “glitches” are not dangerous for patients.

Do solar flares affect the psyche?

Some researchers have identified a correlation between the solar flare and an increase in suicide rates. However, there is no direct evidence. Presumably, geomagnetic storms can desynchronize circadian rhythms associated with the cycle of day and night and the production of melatonin, a hormone that has an anti-stress effect. The pineal gland, which regulates circadian rhythm and melatonin production, is sensitive to changes in the magnetic field. This can affect our mood.

Solar flare, photograph of the Hinode satellite. Observed as two narrow, bright structures near the southern part of the sunspot.

A solar flare is an explosive process of release of energy (light, heat and kinetic) into. Flares in one way or another cover all layers of the solar atmosphere: the photosphere, chromosphere and solar corona. It should be noted that solar flares and coronal mass ejections are different and independent phenomena solar activity. The energy release of a powerful solar flare can reach 6 × 10 25 joules, which is about 1 ⁄ 6 of the energy released by the Sun per second, or 160 billion megatons of TNT, which, for comparison, is the approximate amount of global electricity consumption in 1 million years.

Description

The duration of the pulse phase of solar flares usually does not exceed several minutes, and the amount of energy released during this time can reach billions of megatons of TNT equivalent. The flare energy is traditionally determined in the visible range of electromagnetic waves by the product of the glow area in the hydrogen emission line H α, which characterizes the heating of the lower chromosphere, and the brightness of this glow, associated with the power of the source.

In recent years, a classification based on patrol uniform measurements on a series, mainly GOES, of the amplitude of thermal X-ray bursts in the energy range 0.5-10 keV (with a wavelength of 0.5-8 angstroms) is also often used. The classification was proposed in 1970 by D. Baker and was initially based on measurements from the Solrad satellites. According to this classification, a solar flare is assigned a score - a designation made from a Latin letter and an index behind it. The letter may be A, B, C, M or X depending on the magnitude of the peak X-ray intensity reached by the flare:

The index specifies the value of the flare intensity and can be from 1.0 to 9.9 for the letters A, B, C, M and more for the letter X. For example, a flare of M8.3 on February 12, 2010 corresponds to a peak intensity of 8. 3×10 −5 W/m2. The most powerful (as of 2010) flare recorded since 1976, which occurred on November 4, 2003, was assigned a score of X28, so its peak X-ray intensity was 28 × 10 −4 W/m 2 . It should be noted that the registration of X-ray radiation from the Sun, since it is completely absorbed by the atmosphere, became possible starting from the first launch of Sputnik 2 with the appropriate equipment, therefore data on the intensity of X-ray radiation from solar flares before 1957 are completely absent.

Measurements in different wavelength ranges reflect different processes in flashes. Therefore, the correlation between two flare activity indices exists only in a statistical sense, so for individual events one index can be high and the second low and vice versa.

Solar flares typically occur where sunspots of opposite magnetic polarity interact, or more precisely, near the neutral magnetic field line separating regions of north and south polarity. The frequency and power of solar flares depend on the phase of the 11-year solar cycle.

Consequences

Solar flares are of practical importance, for example, in studying the elemental composition of the surface of a celestial body with a rarefied atmosphere or in its absence, acting as an exciter of X-ray radiation for X-ray fluorescence spectrometers installed on board spacecraft.

Hard ultraviolet and X-ray radiation from flares is the main factor responsible for the formation of the ionosphere, which can also significantly change the properties of the upper atmosphere: its density increases significantly, which leads to a rapid decrease in the altitude of the satellite’s orbit (up to a kilometer per day).

Plasma clouds emitted during flares lead to the occurrence of geomagnetic storms, which in a certain way affect technology and biological objects.

Forecasting

The modern forecast of solar flares is based on an analysis of the solar magnetic fields. However, the magnetic structure of the Sun is so unstable that it is currently not possible to predict a flare even a week in advance. NASA gives a forecast for a very short period, from 1 to 3 days: on quiet days on the Sun, the probability of a strong flare is usually indicated in the range of 1-5%, and during active periods it increases only to 30-40%.