ACTIVITY OF THE EARTH'S GEOMAGNETIC FIELD (MAGNETIC STORM)
A magnetic storm is a temporary disturbance of the Earth's magnetosphere under the influence of solar wind blows. The strengthening of the solar wind compresses the magnetosphere. In addition, the magnetic field of the solar wind interacts with the magnetic field of the Earth, transferring some of its energy into the magnetosphere. This leads to an acceleration of the plasma motion through the magnetosphere and an increase in the strength of electric currents.
The disturbances causing the storm can be the cause of a coronal ejection or a high-speed flow of the solar wind from regions of weak magnetic fields on the surface of the Sun. The frequency of increases and decreases in magnetic storms is associated with the sunspot cycle. Coronary storms occur more often at maximum solar activity, and flux storms - at minimum.
The impact of magnetic storms on the Earth is called space weather. Space weather has the following impacts on economic activities:
1. Power grids. When a magnetic field moves near a conductor, an induced current arises in it, which can lead to overloads in power grids. Thus, magnetic storms can cause large-scale power outages and even lead to rolling blackouts.
2. Communication. Communication media using high frequency (3-30 MHz) use
the ionosphere to transmit the over-reflected signal over long distances. Magnetic storms in the ionosphere can lead to interference at any geographic latitude, especially near the magnetic poles of the Earth. Telegraph lines are also susceptible to interference. In addition, the magnetic field can damage communication satellites, which has an effect on satellite TV, telephony and the Internet.
3. Navigation systems. Satellite navigation systems such as GPS are susceptible to magnetic storms due to changes in the speed of propagation of radio waves in the atmosphere.
4. Damage to satellites. Magnetic storms increase the heating of the earth's surface from ultraviolet radiation. Rising upwards by 1 km or more, hot currents can change the speed and trajectories of orbiting satellites and even disable them.
5. Geological exploration work. The Earth's magnetic field is used by geologists to study underground geological structures. Usually, this is how oil, gas and deposits of various minerals are found. This can only be done with an undisturbed magnetic field.
6. Pipelines. Rapidly changing magnetic fields can generate magnetically induced currents in pipes. This leads to malfunctioning water meters and increased pipe corrosion.
7. Radiation exposure. Intense solar flares release highly charged particles that can cause radiation contamination in humans and other mammals. The penetration of such particles into the body causes destruction of chromosomes, cancerous tumors and many other problems. Astronauts in near-earth orbit are especially susceptible to such radiation.
8. Effects on humans and animals. Scientists have not yet come to a consensus on whether magnetic storms have effects on animals, such as throwing whales ashore. In addition, malfunctions are possible in migratory animals, as well as in bees oriented along the lines of the Earth's magnetic field. It is also not entirely clear whether magnetic storms have a direct impact on human health. It has been noticed that some people are exposed to increased stress 1-2 days before the onset of a magnetic storm, that is, at the time of the appearance of solar flares. The branch of science that studies the influence of magnetic field fluctuations on living organisms is called geobiology.
Measurement and forecast of magnetic storms. What is K-Index?
The forecast of magnetic storms is based on the analysis of data from telescopes and satellites. At the same time, the current state of the Sun's corona, active regions near the eastern limb and the central meridian are analyzed. The most accurate forecasts are up to two days.
To determine the disturbance of the Earth's magnetic field, the so-called K-index is used. This is the deviation of the magnetic field from the norm at three-hour intervals. The K-index is defined in the range from 0 to 9. The higher the value, the more disturbed the Earth's magnetic field. Values greater than 4 correspond to magnetic storms.
Environmental monitoring of air pollution directorate. Agency for Hydrometeorology of the
Committee for Environmental Protection under the Government of the Republic of Tajikistan