Indexes of geomagnetic activity influence on humans. Magnetic storms. — Geomagnetic storms scale. am, an, as indices

Now: Kp= 6 storm

In fact, in some places the surge of the storm rose to 7-8 points

State of the magnetic field depending on the Kp index

Kp< 2 - спокойное;

Kp = 2, 3 - slightly disturbed;

Kp = 4 - disturbed;

Kp = 5, 6 - magnetic storm;

Kp = 7, 8 - strong magnetic storm;

Kp = 9 - a very strong geomagnetic storm.

G A geomagnetic storm is a disturbance in 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. Geomagnetic storms cause rapid and strong changes in the Earth's magnetic field, occurring during periods of increased solar activity. This phenomenon is one of the most important elements of solar-terrestrial physics and its practical part, usually referred to as “Space weather”.

As a result of solar flares, a huge amount of matter (mainly protons and electrons) is ejected into outer space, part of which, moving at a speed of 400–1000 km/s, reaches the earth’s atmosphere in one or two days. The Earth's magnetic field captures charged particles from outer space. Too strong a flow of particles disturbs the planet's magnetic field, causing the magnetic field characteristics to change quickly and greatly.

The G-index is a five-point scale of magnetic storm strength that 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.

Magnetic storms also have an impact on people's health and well-being. They are dangerous primarily for those who suffer from arterial hypertension and hypotension, and heart disease. Approximately 70% of heart attacks, hypertensive crises and strokes occur during solar storms.

Magnetic storms are often accompanied by headaches, migraines, rapid heartbeat, insomnia, poor health, decreased vitality, and pressure changes. Scientists attribute this to the fact that when the magnetic field fluctuates, capillary blood flow slows down and tissue oxygen starvation occurs.

Soviet biophysicist A.L. Chizhevsky in his monograph “The Terrestrial Echo of Solar Storms,” he analyzed a large amount of historical material and discovered a correlation between the maxima of solar activity and mass cataclysms on Earth. Hence the conclusion was made about the influence of the 11-year cycle of solar activity (periodic increase and decrease in the number of sunspots) on climatic and social processes on the ground. Chizhevsky established that during periods of increased solar activity (a large number of sunspots) wars, revolutions, natural disasters, catastrophes, epidemics occur on Earth, and the intensity of bacterial growth increases (“Chizhevsky-Velkhover effect”).

• Solar cosmic rays (SCR) are protons, electrons, nuclei formed in solar flares and reaching the Earth's orbit after interacting with the interplanetary medium.
• Magnetospheric storms and substorms caused by the arrival of an interplanetary shock wave, associated with both CME and COW, and with high-speed solar wind streams;
• Ionizing electromagnetic radiation (IER) from solar flares, causing heating and additional ionization of the upper atmosphere;
• Increases in the fluxes of relativistic electrons in the Earth's outer radiation belt associated with the arrival of high-speed solar wind streams to the Earth.

Solar cosmic rays (SCR)

The energetic particles formed in flares - protons, electrons, nuclei - after interacting with the interplanetary medium can reach the Earth's orbit. It is generally accepted that the largest contribution to the total dose comes from solar protons with an energy of 20-500 MeV. The maximum flux of protons with energies above 100 MeV from a powerful flare on February 23, 1956 was 5000 particles per cm -2 s -1 .
(See the materials on the topic “Solar Cosmic Rays” for more details).
Main source of SCR– solar flares, in rare cases - decay of a prominence (fiber).

SCR as the main source of radiation hazard in OKP

Fluxes of solar cosmic rays significantly increase the level of radiation hazard for astronauts, as well as crews and passengers of high-altitude aircraft on polar routes; lead to the loss of satellites and failure of equipment used on space objects. The harm that radiation causes to living beings is quite well known (for more details, see the materials on the topic “How does space weather affect our lives?”), but in addition, a large dose of radiation can also damage electronic equipment installed on spacecraft (see Read more about Lecture 4 and materials on topics on the impact of the external environment on spacecraft, their elements and materials).
The more complex and modern the microcircuit, the smaller sizes each element and the greater the likelihood of failures, which can lead to its incorrect operation and even stopping the processor.
Let us give a clear example of how high-energy SCR fluxes affect the state of scientific equipment installed on spacecraft.

For comparison, the figure shows photographs of the Sun taken by the EIT (SOHO) instrument, taken before (07:06 UT 28/10/2003) and after a powerful solar flare that occurred around 11:00 UT 28/10/2003, after which NCP fluxes of protons with energies of 40-80 MeV increased by almost 4 orders of magnitude. The amount of “snow” in the right figure shows how damaged the recording matrix of the device is by the fluxes of flare particles.

The influence of increases in SCR fluxes on the Earth's ozone layer

Since the sources of nitrogen and hydrogen oxides, the content of which determines the amount of ozone in the middle atmosphere, can also be high-energy particles (protons and electrons) of SCRs, their influence should be taken into account in photochemical modeling and interpretation of observational data at the moments of solar proton events or strong geomagnetic disturbances.

Solar proton events

The role of 11-year GCR variations in assessing the radiation safety of long-term space flights

When assessing the radiation safety of long-term space flights (such as, for example, the planned expedition to Mars), it becomes necessary to take into account the contribution of galactic cosmic rays (GCRs) to the radiation dose (for more details, see lecture 4). In addition, for protons with energies above 1000 MeV, the magnitude of the GCR and SCR fluxes becomes comparable. By revising various phenomena on the Sun and in the heliosphere, over time intervals of several decades or more, their determining factor is the 11-year and 22-year cyclicity of the solar process. As can be seen from the figure, the GCR intensity changes in antiphase with the Wolf number. This is very important, since at SA minimum the interplanetary medium is weakly disturbed and GCR fluxes are maximum. Having a high degree of ionization and being all-pervasive, during periods of minimum SA GCRs determine dose loads on humans in space and aviation flights. However, solar modulation processes turn out to be quite complex and cannot be reduced only to anti-correlation with the Wolf number. .

The figure shows the modulation of CR intensity in the 11-year solar cycle.

Solar electrons

High-energy solar electrons can cause volume ionization of spacecraft, and also act as “killer electrons” for microcircuits installed on spacecraft. Due to SCR fluxes, short-wave communications in the polar regions are disrupted and failures occur in navigation systems.

Magnetospheric storms and substorms

Others important consequences manifestations of solar activity that affect the state of near-Earth space are magnetic storms– strong (tens and hundreds of nT) changes in the horizontal component of the geomagnetic field measured on the Earth’s surface at low latitudes. Magnetospheric storm is a set of processes occurring in the Earth’s magnetosphere during a magnetic storm, when there is a strong compression of the magnetosphere boundary on the day side, other significant deformations of the structure of the magnetosphere, and a ring current of energetic particles is formed in the inner magnetosphere.
The term "substorm" was introduced in 1961. S-I. Akasofu to designate auroral disturbances in the auroral zone lasting about an hour. In the magnetic data, bay-shaped disturbances were identified even earlier, coinciding in time with a substorm in the auroras. Magnetospheric substorm is a set of processes in the magnetosphere and ionosphere, which in the most general case can be characterized as a sequence of processes of energy accumulation in the magnetosphere and its explosive release. Source of magnetic storms− the arrival of high-speed solar plasma (solar wind), as well as COW and the associated shock wave, to the Earth. High-speed solar plasma flows, in turn, are divided into sporadic, associated with solar flares and CMEs, and quasi-stationary, arising above coronal holes. Magnetic storms, in accordance with their source, are divided into sporadic and recurrent. (See lecture 2 for more details).

Geomagnetic indices – Dst, AL, AU, AE

The numerical characteristics reflecting geomagnetic disturbances are various geomagnetic indices– Dst, Kp, Ap, AA and others.
The amplitude of variations in the Earth's magnetic field is often used as the most general characteristic of the strength of magnetic storms. Geomagnetic index Dst contains information about planetary disturbances during geomagnetic storms.
The three-hour index is not suitable for studying substorm processes; during this time a substorm can begin and end. Detailed structure of magnetic field fluctuations due to auroral zone currents ( auroral electric jet) characterizes auroral electric jet index AE. To calculate the AE index, we use magnetograms of H-components observatories located at auroral or subauroral latitudes and evenly distributed in longitude. Currently, AE indices are calculated from data from 12 observatories located in the northern hemisphere at different longitudes between 60 and 70° geomagnetic latitude. To numerically describe substorm activity, geomagnetic indices AL (the largest negative variation of the magnetic field), AU (the largest positive variation of the magnetic field) and AE (the difference between AL and AU) are also used.

Dst index for May 2005

Kr, Ar, AA indices

The geomagnetic activity index Kp is calculated every three hours based on magnetic field measurements at several stations located in various parts Earth. It has levels from 0 to 9, each next level of the scale corresponds to variations 1.6-2 times greater than the previous one. Strong magnetic storms correspond to levels of Kp greater than 4. So-called superstorms with Kp = 9 occur quite rarely. Along with Kp, the Ap index is also used, equal to the average amplitude of geomagnetic field variations across the globe per day. It is measured in nanoteslas (the earth's field is approximately
50,000 nT). The level Kp = 4 approximately corresponds to an Ap equal to 30, and the level Kp = 9 corresponds to an Ap greater than 400. The expected values ​​of such indices constitute the main content of the geomagnetic forecast. The Ap index began to be calculated in 1932, so for earlier periods the AA index is used - the average daily amplitude of variations, calculated from two antipodal observatories (Greenwich and Melbourne) since 1867.

The complex influence of SCRs and storms on space weather due to the penetration of SCRs into the Earth's magnetosphere during magnetic storms

From the point of view of the radiation hazard posed by SCR fluxes for high-latitude segments of the orbits of spacecraft such as the ISS, it is necessary to take into account not only the intensity of SCR events, but also the boundaries of their penetration into the Earth’s magnetosphere(See Lecture 4 for more details.) Moreover, as can be seen from the figure above, SCRs penetrate quite deeply even for magnetic storms of small amplitude (-100 nT or less).

Assessment of radiation hazard in high-latitude regions of the ISS trajectory based on data from low-orbit polar satellites

Estimates of radiation doses in high-latitude regions of the ISS trajectory, obtained based on data on the spectra and limits of SCR penetration into the Earth's magnetosphere according to the Universitetsky-Tatyana satellite data during solar flares and magnetic storms of September 2005, were compared with doses experimentally measured on the ISS in high latitude areas. From the given figures it is clearly seen that the calculated and experimental values ​​are consistent, which indicates the possibility of estimating radiation doses in different orbits using data from low-altitude polar satellites.

Map of doses on the ISS (IBS) and comparison of calculated and experimental doses.

Magnetic storms as a cause of radio communication disruption

Magnetic storms lead to strong disturbances in the ionosphere, which in turn negatively affect the state radio broadcast. In the subpolar regions and auroral oval zones, the ionosphere is associated with the most dynamic regions of the magnetosphere and is therefore most sensitive to such influences. Magnetic storms in high latitudes can almost completely block radio broadcasts for several days. At the same time, other areas of activity, for example, air travel, also suffer. Another negative effect associated with geomagnetic storms is the loss of orientation of satellites, the navigation of which is carried out along the geomagnetic field, which experiences strong disturbances during the storm. Naturally, during geomagnetic disturbances, problems arise with radar.

The influence of magnetic storms on the functioning of telegraph and power lines, pipelines, railways

Variations in the geomagnetic field that occur during magnetic storms in polar and auroral latitudes (according to the well-known law of electromagnetic induction) generate secondary electric currents in the conducting layers of the Earth's lithosphere, in salt water and in artificial conductors. The induced potential difference is small and amounts to approximately a few volts per kilometer, but in long conductors with low resistance - communication and power lines (power lines), pipelines, rails railways − the total strength of induced currents can reach tens and hundreds of amperes.
The least protected from such influence are overhead low-voltage communication lines. Thus, significant interference that occurred during magnetic storms was noted already on the very first telegraph lines built in Europe in the first half of the 19th century. Geomagnetic activity can also cause significant problems for railway automation, especially in the polar regions. And in oil and gas pipelines stretching for many thousands of kilometers, induced currents can significantly accelerate the process of metal corrosion, which must be taken into account when designing and operating pipelines.

Examples of the impact of magnetic storms on the functioning of power lines

A major accident that occurred during the severe magnetic storm of 1989 in Canada's power grid clearly demonstrated the danger of magnetic storms for power lines. Investigations showed that transformers were the cause of the accident. The fact is that the constant current component introduces the transformer into a non-optimal operating mode with excessive magnetic saturation of the core. This leads to excessive energy absorption, overheating of the windings and, ultimately, to a breakdown of the entire system. The subsequent analysis of the performance of all power plants North America revealed a statistical relationship between the number of failures in high-risk areas and the level of geomagnetic activity.

The influence of magnetic storms on human health

Currently, there are results of medical studies proving the existence of a human reaction to geomagnetic disturbances. These studies show that there is a fairly large category of people on whom magnetic storms have a negative effect: human activity is inhibited, attention is dulled, and chronic diseases are exacerbated. It should be noted that studies of the impact of geomagnetic disturbances on human health are just beginning, and their results are quite controversial and contradictory (for more details, see the materials on the topic “How does space weather affect our lives?”).
However, most researchers agree that in this case there are three categories of people: for some, geomagnetic disturbances have a depressing effect, for others, on the contrary, they have an exciting effect, and for others, no reaction is observed.

Ionospheric substorms as a space weather factor

Substorms are a powerful source electrons in the outer magnetosphere. The fluxes of low-energy electrons increase greatly, which leads to a significant increase in electrification of spacecraft(for more details, see the materials on the topic "Electrification of spacecraft"). During strong substorm activity, electron fluxes in the Earth's outer radiation belt (ERB) increase by several orders of magnitude, which poses a serious danger to satellites whose orbits cross this region, since a sufficiently large amount of electrons accumulates inside the spacecraft. volumetric charge leading to failure of on-board electronics. As an example, we can cite problems with the operation of electronic instruments on the Equator-S, Polag and Calaxy-4 satellites, which arose against the background of prolonged substorm activity and, as a consequence, very high fluxes of relativistic electrons in the outer magnetosphere in May 1998.
Substorms are an integral companion of geomagnetic storms, however, the intensity and duration of substorm activity has an ambiguous relationship with the power of the magnetic storm. An important manifestation of the “storm-substorm” connection is the direct influence of the power of a geomagnetic storm on the minimum geomagnetic latitude at which substorms develop. During strong geomagnetic storms, substorm activity can descend from high geomagnetic latitudes, reaching mid-latitudes. In this case, at mid-latitudes there will be a disruption of radio communications caused by the disturbing effect on the ionosphere of energetic charged particles generated during substorm activity.

The relationship between solar and geomagnetic activity - current trends

In some contemporary works devoted to the problem of space weather and space climate, the idea is expressed about the need to separate solar and geomagnetic activity. The figure shows the difference between monthly average sunspot values, traditionally considered an indicator of the SA (red), and the AA index (blue), which shows the level of geomagnetic activity. It can be seen from the figure that the coincidence is not observed for all SA cycles.
The fact is that a large proportion of SA maxima are made up of sporadic storms, for which flares and CMEs are responsible, that is, phenomena occurring in regions of the Sun with closed power lines. But at SA minima, most storms are recurrent, caused by the arrival to Earth of high-speed solar wind streams flowing from coronal holes - regions with open field lines. Thus, the sources of geomagnetic activity, at least for SA minima, have a significantly different nature.

Ionizing electromagnetic radiation from solar flares

As another important factor space weather Ionizing electromagnetic radiation (IER) from solar flares should be noted separately. During quiet times, EI is almost completely absorbed at high altitudes, causing ionization of air atoms. During solar flares, EI fluxes from the Sun increase by several orders of magnitude, which leads to warming up And additional ionization of the upper atmosphere.
As a result heating under the influence of electrical energy, the atmosphere is “inflated”, i.e. its density at a fixed height increases greatly. This poses a serious danger for low-altitude satellites and manned spacecraft, since when entering the dense layers of the atmosphere, the spacecraft can quickly lose altitude. This fate befell the American space station Skylab in 1972 during a powerful solar flare - the station did not have enough fuel to return to its previous orbit.

Absorption of shortwave radio waves

Absorption of shortwave radio waves is the result of the fact that the arrival of ionizing electromagnetic radiation - UV and X-ray radiation from solar flares causes additional ionization of the upper atmosphere (see for more details in the materials on the topic "Transient light phenomena in the upper atmosphere of the Earth"). This leads to a deterioration or even complete cessation of radio communications on the illuminated side of the Earth for several hours)