Main factors of space weather. Geomagnetic field: features, structure, characteristics and history of research

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 much particle flow disturbs the planet's magnetic field, causing the magnetic field characteristics to change quickly and dramatically.

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 affect 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. From this, a conclusion was drawn 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 Earth. 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”).

The magnetic storm informer shows the average predicted values ​​of the global geomagnetic index ( Cr-index) Earth, based on geophysical data from twelve observatories around the world.
Cr-index – characterizes the geomagnetic field on a global scale.
At different parts of the earth's surface, Cr-index differs within 1-2 units. The entire Cr-index range is from 1 to 9 units. On different continents, the index may differ by one or two units (+/-), with the entire range being from zero to nine.
The informer forecasts magnetic storms for 3 days, eight values ​​per day, for every 3 hours of the day.

Green color is a safe level of geomagnetic activity.
Red color – magnetic storm (Cr-index > 5).
The higher the red vertical line, the stronger the magnetic storm.

The level at which noticeable effects on the health of weather-sensitive people are likely (Cr-index > 6) is marked with a horizontal red line.

The following Cr-index coefficients are accepted:
The following magnetic field indices are relatively favorable for health: Cr = 0-1 – geomagnetic situation is calm; Cr = 1-2 – geomagnetic conditions from calm to slightly disturbed; Cr = 3-4 – from slightly disturbed to disturbed. The following magnetic field indices are unfavorable for health: Cr = 5-6 – magnetic storm; Cr = 7-8 – large magnetic storm; Cr = 9 – maximum possible value
Based on materials from www.meteofox.ru

INFLUENCE OF COSMOPHYSICAL FACTORS ON THE BIOSPHERE.

An analysis of facts confirming the influence of the Sun, as well as electromagnetic fields of natural and artificial origin on living organisms, was carried out. Assumptions have been made about the sources and mechanism of human reaction to magnetic storms, the nature of “bioeffective frequency windows,” and sensitivity to electromagnetic fields of various origins. The socio-historical aspect of the influence of space weather on people is discussed.

The full text of the article is located at this address

NATURE ALSO HAS SPACE WEATHER

Candidate of Physical and Mathematical Sciences A. PETRUKOVICH, Doctor of Physical and Mathematical Sciences L. ZELENY
Space Research Institute.

In the 20th century, earthly civilization imperceptibly crossed a very important milestone in its development. The technosphere - the area of ​​human activity - has expanded far beyond the boundaries of the natural habitat - the biosphere. This expansion is both spatial - due to the exploration of outer space, and qualitative in nature - due to the active use of new types of energy and electromagnetic waves. But still, for aliens looking at us from a distant star, the Earth remains just a grain of sand in the ocean of plasma that fills the Solar System and the entire Universe, and our stage of development can be compared more to the first steps of a child than to the achievement of maturity. The new world that has opened up to humanity is no less complex and, as is the case on Earth, is not always friendly. Mastering it was not without losses and mistakes, but we are gradually learning to recognize new dangers and overcome them. And there are many of these dangers. This includes background radiation in the upper atmosphere, loss of communication with satellites, aircraft and ground stations, and even catastrophic accidents on communication and power lines that occur during powerful magnetic storms.

The sun is our everything
The sun is truly the center of our world. For billions of years it holds the planets near itself and heats them. The Earth is acutely aware of changes in solar activity, which currently manifest themselves mainly in the form of 11-year cycles. During bursts of activity that become more frequent at the maxima of the cycle, intense flows of X-ray radiation and energetic charged particles - solar cosmic rays - are born in the solar corona, and huge masses of plasma and magnetic field (magnetic clouds) are ejected into interplanetary space. Although the magnetosphere and atmosphere of the Earth quite reliably protect all living things from the direct effects of solar particles and radiation, many human creations, for example, radio electronics, aviation and space technology, communication and power lines, pipelines, turn out to be very sensitive to electromagnetic and corpuscular influences coming from near-Earth space.
Let us now get acquainted with the most practically important manifestations of solar and geomagnetic activity, often called “space weather”.

Dangerous! Radiation!
Perhaps one of the most striking manifestations of the hostility of outer space towards man and his creations, besides, of course, an almost complete vacuum by earthly standards, is radiation - electrons, protons and heavier nuclei, accelerated to enormous speeds and capable of destroying organic and inorganic molecules. The harm that radiation causes to living beings is well known, but a sufficiently large dose of radiation (that is, the amount of energy absorbed by a substance and used for its physical and chemical destruction) can also damage radio-electronic systems. Electronics also suffer from “single failures,” when particularly high-energy particles, penetrating deep inside an electronic microcircuit, change the electrical state of its elements, knocking out memory cells and causing false positives. The more complex and modern the chip, the smaller the size of each element and the greater the likelihood of failures, which can lead to its incorrect operation and even to the processor stopping. This situation is similar in its consequences to a computer suddenly freezing in the middle of typing, with the only difference being that the satellite equipment, generally speaking, is designed to operate automatically. To correct the error, you have to wait for the next communication session with the Earth, provided that the satellite is able to communicate.

The first traces of radiation of cosmic origin on Earth were discovered by the Austrian Victor Hess back in 1912. Later, in 1936, he received the Nobel Prize for this discovery. The atmosphere effectively protects us from cosmic radiation: very few so-called galactic cosmic rays with energies above several gigaelectronvolts generated outside the Solar System reach the Earth's surface. Therefore, the study of energetic particles outside the Earth's atmosphere immediately became one of the main scientific tasks of the space age. The first experiment to measure their energy was carried out by a group of Soviet researcher Sergei Vernov in 1957. The reality exceeded all expectations - the instruments went off scale. A year later, the leader of a similar American experiment, James Van Allen, realized that this was not a malfunction of the device, but real, powerful flows of charged particles that were not related to galactic rays. The energy of these particles is not high enough for them to reach the surface of the Earth, but in space this “disadvantage” is more than compensated by their quantity. The main source of radiation in the vicinity of the Earth turned out to be high-energy charged particles “living” in the Earth’s inner magnetosphere, in the so-called radiation belts.

It is known that the almost dipole magnetic field of the Earth's inner magnetosphere creates special zones of “magnetic bottles” in which charged particles can be “captured” for a long time, rotating around the lines of force. In this case, the particles are periodically reflected from the near-Earth ends of the field line (where the magnetic field increases) and slowly drift around the Earth in a circle. In the most powerful inner radiation belt, protons with energies up to hundreds of megaelectronvolts are well contained. The radiation doses that can be received during its flight are so high that only research satellites risk being kept in it for a long time. Manned spacecraft are hidden in lower orbits, and most communications satellites and navigation spacecraft are in orbits above this belt. The inner belt comes closest to the Earth at the points of reflection. Due to the presence of magnetic anomalies (deviations of the geomagnetic field from an ideal dipole) in those places where the field is weakened (above the so-called Brazilian anomaly), particles reach heights of 200-300 kilometers, and in those where it is strengthened (above the East Siberian anomaly ), - 600 kilometers. Above the equator, the belt is 1,500 kilometers from the Earth. The inner belt itself is quite stable, but during magnetic storms, when the geomagnetic field weakens, its conventional boundary descends even closer to the Earth. Therefore, the position of the belt and the degree of solar and geomagnetic activity are necessarily taken into account when planning flights of cosmonauts and astronauts working in orbits at an altitude of 300-400 kilometers.

Energetic electrons are most efficiently retained in the outer radiation belt. The “population” of this belt is very unstable and increases many times during magnetic storms due to the injection of plasma from the outer magnetosphere. Unfortunately, it is along the outer periphery of this belt that the geostationary orbit passes, which is indispensable for placing communication satellites: the satellite on it motionlessly “hangs” above one point on the globe (its altitude is about 42 thousand kilometers). Since the radiation dose created by electrons is not so large, the problem of electrifying satellites comes to the fore. The fact is that any object immersed in plasma must be in electrical equilibrium with it. Therefore, it absorbs a certain number of electrons, acquiring a negative charge and a corresponding “floating” potential, approximately equal to the temperature of the electrons, expressed in electron volts. Clouds of hot (up to hundreds of kiloelectron volts) electrons that appear during magnetic storms give satellites an additional and unevenly distributed, due to the difference in the electrical characteristics of surface elements, negative charge. Potential differences between adjacent satellite parts can reach tens of kilovolts, provoking spontaneous electrical discharges that damage electrical equipment. The most famous consequence of this phenomenon was the breakdown of the American TELSTAR satellite during one of the magnetic storms in 1997, which left a significant part of the United States without pager communications. Since geostationary satellites are usually designed to last 10-15 years and cost hundreds of millions of dollars, research into electrification of surfaces in outer space and methods to combat it are usually a trade secret.

Another important and most unstable source of cosmic radiation is solar cosmic rays. Protons and alpha particles, accelerated to tens or hundreds of megaelectronvolts, fill the solar system only briefly after a solar flare, but the intensity of the particles makes them a major source of radiation hazard in the outer magnetosphere, where the geomagnetic field is still too weak to protect satellites. Solar particles, against the background of other, more stable sources of radiation, are also “responsible” for short-term deterioration of the radiation situation in the inner magnetosphere, including at altitudes used for manned flights.

Energetic particles penetrate deepest into the magnetosphere in the subpolar regions, since particles here can freely move most of the way along lines of force almost perpendicular to the Earth's surface. Near-equatorial regions are more protected: there the geomagnetic field, almost parallel to the earth’s surface, changes the trajectory of particles to a spiral one and takes them to the side. Therefore, flight routes passing at high latitudes are much more dangerous from the point of view of radiation damage than those at low latitudes. This threat applies not only to spacecraft, but also to aviation. At altitudes of 9-11 kilometers, where most aviation routes pass, the overall background of cosmic radiation is already so high that the annual dose received by crews, equipment and frequent fliers must be controlled according to the rules established for radiation hazardous activities. Supersonic Concorde passenger planes that fly to even greater altitudes have radiation counters on board and are required to fly south of the shortest northern route between Europe and America if the current radiation level exceeds a safe value. However, after the most powerful solar flares, the dose received even during one flight on a conventional plane can be greater than the dose of one hundred fluorographic examinations, which makes it necessary to seriously consider the issue of completely stopping flights at such times. Fortunately, bursts of solar activity of this level are recorded less often than once per solar cycle - 11 years.

Excited ionosphere
On the lower floor of the electrical solar-terrestrial circuit is the ionosphere - the densest plasma shell of the Earth, literally like a sponge absorbing both solar radiation and the precipitation of energetic particles from the magnetosphere. After solar flares, the ionosphere, absorbing solar X-rays, heats up and inflates, so that the density of plasma and neutral gas at an altitude of several hundred kilometers increases, creating significant additional aerodynamic resistance to the movement of satellites and manned spacecraft. Neglecting this effect can lead to “unexpected” braking of the satellite and loss of its flight altitude. Perhaps the most notorious case of such an error was the fall of the American Skylab station, which was “missed” after the largest solar flare that occurred in 1972. Fortunately, during the descent of the Mir station from orbit, the Sun was calm, which made the work of Russian ballisticians easier.

However, perhaps the most important effect for most inhabitants of the Earth is the influence of the ionosphere on the state of the radio broadcast. Plasma most effectively absorbs radio waves only near a certain resonant frequency, which depends on the density of charged particles and is equal to approximately 5-10 megahertz for the ionosphere. Radio waves of a lower frequency are reflected from the boundaries of the ionosphere, and waves of a higher frequency pass through it, and the degree of distortion of the radio signal depends on the proximity of the wave frequency to the resonant one. The quiet ionosphere has a stable layered structure, allowing, due to multiple reflections, to receive a short-wave radio signal (with a frequency below the resonant one) throughout the globe. Radio waves with frequencies above 10 megahertz travel freely through the ionosphere into outer space. Therefore, VHF and FM radio stations can only be heard in the vicinity of the transmitter, and at frequencies of hundreds and thousands of megahertz they communicate with spacecraft.

During solar flares and magnetic storms, the number of charged particles in the ionosphere increases, and so unevenly that plasma clots and “extra” layers are created. This results in unpredictable reflection, absorption, distortion and refraction of radio waves. In addition, the unstable magnetosphere and ionosphere themselves generate radio waves, filling a wide range of frequencies with noise. In practice, the magnitude of the natural radio background becomes comparable to the level of the artificial signal, creating significant difficulties in the operation of ground and space communication and navigation systems. Radio communication even between neighboring points may become impossible, but in return you can accidentally hear some African radio station, and see false targets on the locator screen (which are often mistaken for “flying saucers”). 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 disturbances coming from the Sun. Magnetic storms in high latitudes can almost completely block radio broadcasts for several days. At the same time, naturally, many other areas of activity, such as air travel, are also frozen. That is why all services that actively use radio communications, back in the middle of the 20th century, became one of the first real consumers of space weather information.

Current jets in space and on Earth
Fans of books about polar travelers have heard not only about interruptions in radio communications, but also about the “crazy needle” effect: during magnetic storms, the sensitive compass needle begins to spin like mad, unsuccessfully trying to keep track of all changes in the direction of the geomagnetic field. Field variations are created by jets of ionospheric currents with a force of millions of amperes - electrojets, which arise in polar and auroral latitudes with changes in the magnetospheric current circuit. In turn, magnetic variations, 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 nearby artificial conductors. The induced potential difference is small and amounts to approximately a few volts per kilometer (the maximum value was recorded in 1940 in Norway and was about 50 V/km), but in long conductors with low resistance - communication and power lines, pipelines, railway rails - complete the strength of induced currents can reach tens and hundreds of amperes.

Low-voltage overhead communication lines are least protected from such influence. Indeed, significant interference that occurred during magnetic storms was already noted on the very first telegraph lines built in Europe in the first half of the 19th century. Reports of these disturbances can probably be considered the first historical evidence of our dependence on space weather. The currently widespread fiber-optic communication lines are insensitive to such influence, but they will not appear in the Russian outback for a long time. Geomagnetic activity should also cause significant problems for railway automation, especially in the polar regions. And in oil pipelines, which often stretch for many thousands of kilometers, induced currents can significantly accelerate the process of metal corrosion.

In power lines operating on alternating current with a frequency of 50-60 Hz, induced currents varying with a frequency of less than 1 Hz practically make only a small constant addition to the main signal and should have little effect on the total power. However, after an accident that occurred during the severe magnetic storm of 1989 in the Canadian energy network and left half of Canada without electricity for several hours, this point of view had to be reconsidered. The cause of the accident turned out to be transformers. Careful research has shown that even a small addition of direct current can destroy a transformer designed to convert alternating current. 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. A subsequent analysis of the performance of all power plants in North America also revealed a statistical relationship between the number of failures in high-risk areas and the level of geomagnetic activity.

Space and man
All of the above-described manifestations of space weather can be conditionally characterized as technical, and the physical basis of their influence is generally known - this is the direct impact of flows of charged particles and electromagnetic variations. However, it is impossible not to mention other aspects of solar-terrestrial connections, the physical essence of which is not entirely clear, namely the influence of solar variability on climate and the biosphere.

Changes in the total flux of solar radiation, even during strong flares, amount to less than one thousandth of the solar constant, that is, it would seem that they are too small to directly change the thermal balance of the Earth's atmosphere. Nevertheless, there is a number of indirect evidence given in the books of A.L. Chizhevsky and other researchers, indicating the reality of solar influence on climate and weather. For example, a pronounced cyclicity of various weather variations with periods close to 11- and 22-year periods of solar activity was noted. This periodicity is also reflected in living nature objects - it is noticeable in the change in the thickness of tree rings.

Currently, forecasts of the influence of geomagnetic activity on people’s health have become widespread (maybe even too widespread). The opinion that people’s well-being depends on magnetic storms is already firmly established in the public consciousness and is even confirmed by some statistical studies: for example, the number of people hospitalized by ambulance and the number of exacerbations of cardiovascular diseases clearly increases after a magnetic storm. However, from the point of view of academic science, not enough evidence has yet been collected. In addition, the human body does not have any organ or cell type that claims to be a sufficiently sensitive receiver of geomagnetic variations. Infrasonic vibrations - sound waves with frequencies of less than one hertz, close to the natural frequency of many internal organs - are often considered as an alternative mechanism for the impact of magnetic storms on a living organism. Infrasound, possibly emitted by the active ionosphere, can have a resonant effect on the human cardiovascular system. It only remains to note that the issues of the relationship between space weather and the biosphere are still waiting for their attentive researcher and to date remain, probably, the most intriguing part of the science of solar-terrestrial connections.

In general, the influence of space weather on our lives can probably be considered significant, but not catastrophic. The Earth's magnetosphere and ionosphere protect us well from cosmic threats. In this sense, it would be interesting to analyze the history of solar activity, trying to understand what may await us in the future. First, there is currently a trend towards an increase in the influence of solar activity, associated with the weakening of our shield - the Earth's magnetic field - by more than 10 percent over the past half century and a simultaneous doubling of the solar magnetic flux, which serves as the main intermediary in the transmission of solar activity.

Secondly, an analysis of solar activity for the entire period of observations of sunspots (since the beginning of the 17th century) shows that the solar cycle, on average equal to 11 years, did not always exist. In the second half of the 17th century, during the so-called Maunder minimum, virtually no sunspots were observed for several decades, which indirectly indicates a minimum of geomagnetic activity. However, this period can hardly be called ideal for life: it coincided with the so-called Little Ice Age - years of abnormally cold weather in Europe. Whether this is a coincidence or not is not known for certain to modern science.

In earlier history, there were also periods of abnormally high solar activity. Thus, in some years of the first millennium AD, auroras were constantly observed in southern Europe, indicating frequent magnetic storms, and the Sun looked dim, possibly due to the presence on its surface of a huge sunspot or coronal hole - another object that causes increased geomagnetic activity. If such a period of continuous solar activity began today, communications and transport, and with them the entire world economy, would be in a dire situation.

* * *
Space weather is gradually taking its rightful place in our consciousness. As with ordinary weather, we want to know what awaits us both in the distant future and in the coming days. To study the Sun, magnetosphere and ionosphere of the Earth, a network of solar observatories and geophysical stations has been deployed, and a whole flotilla of research satellites hovers in near-Earth space. Based on the observations they provide, scientists warn us about solar flares and magnetic storms.

Literature Kippenhan R. 100 Billion Suns: The Birth, Life and Death of Stars. - M., 1990. Kulikov K. A., Sidorenko N. S. Planet Earth. - M., 1972. Miroshnichenko L.I. The sun and cosmic rays. - M., 1970. Parker E. N. Solar wind // Astronomy of the invisible. - M., 1967.
Based on materials from the magazine "Science and Life"

Kp-index, global planetary index of geomagnetic activity. The K-index is a three-hour quasi-logarithmic local index of geomagnetic activity relative to the quiet day curve for a given location. The Kp-index measures the deviation of the most disturbed horizontal component of the magnetic field at fixed stations around the world by their own local K-indexes. The global Kp index is then determined by an algorithm that combines the average values ​​of each station. The Kp index ranges from 0 to 9, where a value of 0 means no geomagnetic activity and a value of 9 means extreme geomagnetic storm.

The Kp Index chart on this website gives an idea of ​​the current geomagnetic conditions, as well as conditions over the past 24 hours and the forecast for the next hour.

Preliminary Kp-index

The preliminary Kp index is the Kp index from NOAA's SWPC, which is updated every 3 hours with an estimate of the measured Kp for the last 3 hours. These periods are: 00:00-03:00 UTC, 03:00-06:00 UTC, etc. The preliminary Kp index consists of 10 values ​​and ranges from 0 to 9 and is an estimate of the observed Kp value during a certain 3 hour period. Therefore, it is not a forecast or an indicator of current conditions, it always shows the Kp value that has been observed during a certain period. The figure below shows a plot of the preliminary Kp index from October 2003 with a 3-day intense geomagnetic storm.

The table below shows the preliminary Kp-index with its 10 values, which represent the G-scale, the specific Kp-index value, the boundary of the auroral oval at local midnight at a specific Kp-value, the description of auroral activity for the specific Kp-index and the frequency of occurrence a certain value of the Kp index during one solar cycle.

Final Kp-index

The final Kp index comes from the GFZ in Potsdam, Germany and is updated twice a month. These are the official final Kp values ​​for scientific research and archival purposes. The final Kp-index differs slightly from the preliminary Kp-index. Unlike the preliminary Kp-index, the final Kp-index is expressed in a scale of thirds and has 28 values, the preliminary Kp-index has only 10 values.

Wing rotation coefficient

The Wing Kp USAF Weather Agency model is expressed on a third scale and has 28 preliminary values. It displays the observed Kp and gives a forecast for the next and next 4 hours. The forecast uses real-time solar wind data from the Deep Space Observatory (DSCOVR). The figure below shows an example of the Wing Kp-index chart available on our website. The solid line shows the predicted Kp-index 1 hour ahead, and the bars indicate the observed Kp-index.

The table below shows the values ​​that the Kp index and Wing Kp index can take. This is 28 values ​​instead of 10 values ​​that the preliminary Kp-index takes.

G-scale

NOAA uses a five-level system called the G-scale to indicate the state of observed and predicted geomagnetic activity. This scale is used to indicate the strength of a geomagnetic storm. This scale ranges from G1 to G5, with G1 being the lowest level and G5 being the highest. No-storm conditions are designated as G0; however, this value is not generally used. Each G-level has a specific Kp-index value associated with it, from 5 - G1 to 9 - G5. The G-scale is used frequently on this site.

What Kp-index value is necessary for the probability of observing the northern lights to appear from my location?

Within the high latitude region, with a Kp index of 4, it becomes possible to observe the northern lights. For middle latitudes, a Kp index of at least 7 is required. For low latitudes, Kp index values ​​of 8 or 9 give a certain degree of probability of observing the northern lights. We have made a convenient list that approximately indicates the Kp-index values ​​required for the location indicated in the table within reach of auroral ovals.

Important! Please note that the locations below provide some degree of probability of seeing the Northern Lights for a given Kp index value under the most favorable local conditions for viewing. This includes, but is not limited to: poor local weather conditions, no clouds, no moonlight and clear view of the horizon.

You have probably paid attention to all sorts of banners and entire pages on amateur radio websites containing various indices and indicators of current solar and geomagnetic activity. These are the ones we need to assess the conditions for the passage of radio waves in the near future. Despite the variety of data sources, one of the most popular are banners provided by Paul Herrman (N0NBH), and completely free of charge.

On his website, you can choose any of the 21 available banners to place in a place convenient for you, or use resources on which these banners are already installed. In total, they can display up to 24 parameters depending on the banner form factor. Below is a summary of each of the banner options. The designations of the same parameters may differ on different banners, so in some cases several options are given.

Solar activity parameters

Solar activity indices reflect the level of electromagnetic radiation and the intensity of the flow of particles, the source of which is the Sun.
Solar Flux Intensity (SFI)

SFI is a measure of the intensity of radiation at 2800 MHz generated by the Sun. This value has no direct effect on the transmission of radio waves, but its value is much easier to measure, and it correlates well with levels of solar ultraviolet and X-ray radiation.
Sunspot number (SN)

SN is not just the number of sunspots. The value of this value depends on the number and size of spots, as well as on the nature of their location on the surface of the Sun. The range of SN values ​​is from 0 to 250. The higher the SN value, the higher the intensity of ultraviolet and x-ray radiation, which increases the ionization of the Earth's atmosphere and leads to the formation of layers D, E and F in it. With an increase in the level of ionization of the ionosphere, the maximum applicable frequency also increases (MUF). Thus, an increase in the SFI and SN values ​​indicates an increase in the degree of ionization in the E and F layers, which in turn has a positive effect on the conditions for the passage of radio waves.

X-Ray Intensity (X-Ray)

The value of this indicator depends on the intensity of X-ray radiation reaching the Earth. The parameter value consists of two parts - a letter reflecting the class of radiation activity, and a number indicating the radiation power in units of W/m2. The degree of ionization of the D layer of the ionosphere depends on the intensity of X-ray radiation. Typically, during the daytime, layer D absorbs radio signals in the low-frequency HF bands (1.8 - 5 MHz) and significantly attenuates signals in the frequency range 7-10 MHz. As the intensity of X-ray radiation increases, the D layer expands and in extreme situations can absorb radio signals in almost the entire HF range, complicating radio communications and sometimes leading to almost complete radio silence, which can last for several hours.

This value reflects the relative intensity of all solar radiation in the ultraviolet range (wavelength 304 angstroms). Ultraviolet radiation has a significant impact on the ionization level of the ionospheric F layer. The 304A value correlates with the SFI value, so its increase leads to improved conditions for the passage of radio waves by reflection from the F layer.

Interplanetary magnetic field (Bz)

The Bz index reflects the strength and direction of the interplanetary magnetic field. A positive value of this parameter means that the direction of the interplanetary magnetic field coincides with the direction of the Earth’s magnetic field, and a negative value indicates a weakening of the Earth’s magnetic field and a decrease in its shielding effects, which in turn increases the impact of charged particles on the Earth’s atmosphere.

Solar Wind/SW

SW is the speed of charged particles (km/h) reaching the Earth's surface. The index value can range from 0 to 2000. A typical value is about 400. The higher the particle speed, the greater the pressure the ionosphere experiences. At SW values ​​exceeding 500 km/h, the solar wind can cause disturbances in the Earth's magnetic field, which will ultimately lead to the destruction of the ionospheric F layer, a decrease in the level of ionosphere ionization and deterioration of transmission conditions in the HF bands.

Proton flux (Ptn Flx/PF)

PF is the density of protons within the Earth's magnetic field. The usual value does not exceed 10. Protons that interact with the Earth's magnetic field move along its lines towards the poles, changing the density of the ionosphere in these zones. At values ​​of proton density above 10,000, the attenuation of radio signals passing through the polar zones of the Earth increases, and at values ​​above 100,000, a complete absence of radio communication is possible.

Electron Flux (Elc Flx/EF)

This parameter reflects the intensity of the electron flow within the Earth's magnetic field. The ionospheric effect from the interaction of electrons with the magnetic field is similar to the proton flux on auroral paths at EF values ​​exceeding 1000.
Noise level (Sig Noise Lvl)

This value in S-meter scale units shows the level of the noise signal that arises as a result of the interaction of the solar wind with the Earth's magnetic field.

Geomagnetic activity parameters

There are two ways in which information about the geomagnetic environment is important for assessing the transmission of radio waves. On the one hand, with increasing disturbance of the Earth's magnetic field, the ionospheric layer F is destroyed, which negatively affects the passage of short waves. On the other hand, conditions arise for auroral passage on VHF.

Indices A and K (A-Ind/K-Ind)

The state of the Earth's magnetic field is characterized by indices A and K. An increase in the value of the K index indicates its increasing instability. K values ​​greater than 4 indicate the presence of a magnetic storm. Index A is used as a base value to determine the dynamics of changes in index K values.
Aurora/Aur Act

The value of this parameter is a derivative of the level of solar energy power, measured in gigawatts, that reaches the polar regions of the Earth. The parameter can take values ​​in the range from 1 to 10. The higher the level of solar energy, the stronger the ionization of the F layer of the ionosphere. The higher the value of this parameter, the lower the latitude of the auroral cap boundary and the higher the probability of auroras occurring. At high values ​​of the parameter, it becomes possible to conduct long-distance radio communications on VHF, but at the same time, polar routes at HF ​​frequencies can be partially or completely blocked.

Latitude (Aur Lat)

The maximum latitude at which an auroral passage is possible.

Maximum usable frequency (MUF)

The value of the maximum applicable frequency measured at the specified meteorological observatory (or observatories, depending on the type of banner), at the given point in time (UTC).

Earth-Moon-Earth Path Attenuation (EME Deg)

This parameter characterizes the amount of attenuation in decibels of the radio signal reflected from the lunar surface on the Earth-Moon-Earth path, and can take the following values: Very Poor (> 5.5 dB), Poor (> 4 dB), Fair (> 2.5 dB), Good (> 1.5 dB), Excellent (

Geomagnetic conditions (Geomag Field)

This parameter characterizes the current geomagnetic situation based on the value of the K index. Its scale is conventionally divided into 9 levels from Inactive to Extreme Storm. With the Major, Severe and Extreme Storm values, the passage on the HF bands deteriorates until they are completely closed, and the likelihood of an auroral passage increases.

In the absence of a program, you can make a good estimate forecast yourself. Obviously, high solar flux index values ​​are good. Generally speaking, the more intense the flow, the better the conditions will be on the high frequency HF bands, including the 6 m band. However, the flow values ​​​​from previous days should also be taken into account. Maintaining large values ​​for several days will ensure a higher degree of ionization of the F2 layer of the ionosphere. Typically, values ​​greater than 150 will guarantee good HF transmission. High levels of geomagnetic activity also have an unfavorable side effect, significantly reducing the MUF. The higher the level of geomagnetic activity according to the Ap and Kp indices, the lower the MUF. The actual MUF values ​​depend not only on the strength of the magnetic storm, but also on its duration.