Magnetosphere of the Earth: the consequences of its change. The outer shells of the Earth

Magnetosphere envelops any body with a magnetic field. It appears because the particles with charges deviate from the original line of motion under the influence of internal magnetism. The meeting place for solar energy and magnetic field forms a plasma covering the magnetosphere.

Influence of the Sun on the Earth

The sun emits a large amount of energy, which constantly expands, "evaporates" outside. This expansion is called the solar wind.

The solar wind spreads in any direction, filling all interplanetary space. For this reason, a plasma formation is formed in the interstellar region, called the solar wind plasma.

The solar plasma moves spirally, on average within 4 days overcomes the interval between the Sun and the Earth.

The sun gives off energy, thanks to which life on Earth continues. However, the Sun emanates dangerous radiation, destructive for all living beings on our planet. When the Earth moves around the Sun, radiation is distributed unevenly throughout the year. For this reason, the seasons change.

What protects the Earth?

The natural structure of the planet Earth protects it from harmful solar radiation. The Earth is surrounded by several shells:

• Magnetosphere, which protects against radiation solar flux;
• Ionosphere, absorbing X-ray and ultraviolet radiation;
• The ozone layer, restraining residual amounts of ultraviolet radiation.

As a result, the Earth's biosphere (living environment of living organisms) is completely protected.

The Earth's magnetosphere is a protective layer, the furthest from the center of the planet. It is a barrier to the solar wind plasma. For this reason, the Sun's plasma flows around the Earth, forming a cavity formation, in which the geomagnetic field is hidden .

Why is there a magnetic field?

The causes of terrestrial magnetism are hidden inside the planet. As is known about the structure of the planet Earth, it consists of:

• Core;
• Mantle;
• The earth's crust.

Around the planet there are various fields, including gravitational and magnetic. Gravity in the simplest sense is the attraction of the earth for all material particles.

Earth magnetism consists in phenomena occurring at the boundaries of the core and mantle. The planet itself is a huge magnet, a uniformly magnetized sphere.

The reason for any magnetic field is an electric current or an uninterrupted magnetization. Scientists dealing with the problem of magnetism of the Earth, find out:

• The causes of the magnetic attraction of the Earth;
• Establish the connections between terrestrial magnetism and its sources;
• Determine the distribution and direction of the magnetic field on the planet.

These studies are carried out by means of magnetic surveys, as well as through observations in observatories - special points in different regions of the globe.

How is the magnetosphere arranged?

The appearance and arrangement of the magnetosphere are produced:

• Solar wind;
• Terrestrial magnetism.

The solar wind is the output of the plasma, distributed from the Sun in any direction. The wind speed near the earth's surface is 300-800 km / s. The solar wind is filled with protons, electrons, alpha particles and is characterized by quasineutrality. The solar wind is endowed with solar magnetism, moved by plasma very far.

The Earth's magnetosphere is a rather complicated cavity. All its sections are filled with plasma processes, in which the mechanisms of particle acceleration are of great importance. From the solar side, the distance from the center to the Earth's boundaries is determined by the power of the solar wind and can reach from 60 to 70 thousand kilometers, which is equal to 10-12 radii of the Earth Re. Re equals 6,371 km.

The boundaries of the magnetosphere are different depending on the location in relation to the Sun. Such a border on the sunny side is similar in shape to a shell. Its approximate distance is 15 Re. On the dark side, the magnetosphere takes the form of a cylindrical tail, its radius is 20-25 Re, its length is more than 200 Re, the ending is unknown.

In the magnetosphere there are regions with high-energy particles, they are called "radiation belts." The magnetosphere is capable of initiating various oscillations and is itself a source of radiation radiation, some of which can penetrate to Earth.

Plasma seeps into the Earth's magnetosphere through intervals between magnetopause traits - polar cusps, and also due to hydromagnetic phenomena and instabilities.

The activity of the magnetic field

The Earth's magnetosphere affects geomagnetic activity, geomagnetic storms and substorms.

It protects life on Earth. Without her, life would stop. According to scientists, the oceans of Mars and its atmosphere went into space due to the undisguised influence of the solar wind. Similarly, the waters of Venus were blown into space by the solar stream.

The magnetosphere is also found in Jupiter, Uranus, Saturn and Neptune. At Mars and Mercury the magnetic shells are insignificant. Venus does not have it at all, the solar wind manages to cope with the ionosphere.

Field Features

The main property of a magnetic field is tension. Magnetic tension is a vector quantity. The magnetic field of the planet is represented with the help of lines of force, the tangents to them show the direction of the tension vector.

The intensity of the magnetic field today is 0.5 Oersted or 0.1 A / m. Scientists allow fluctuations in magnitude in the past. But the geomagnetic field has not changed for the last 2-3.5 billion years.

Points on Earth, where the tension is vertically directed, are called magnetic poles. There are two of them on Earth:

• Northern;
• Southern.

A straight line passes through both poles - the magnetic axis. A circle located perpendicular to the axis is the magnetic equator. The field strength in the equator is horizontal.

Magnetic poles

The magnetic poles do not correspond to the usual geographic poles. Geographic poles are placed along the geographic axis along which the planet rotates. When the Earth moves around the Sun, the direction of the earth's axis remains.

The compass needle points to the magnetic north pole. Magnetic observatories measure the fluctuations of the magnetic field during the day, some of them are engaged every second measurement.

From the North Pole to the South there are magnetic meridians. The angle between the magnetic and geographic meridians is called magnetic declination. Any point on earth has its own declination angle.

At the equator, the magnet arrow is placed horizontally. When moving to the north, the upper end of the arrow rushes down. The angle between the arrow and the horizontal surface is the magnetic inclination. In the field of poles, the inclination is the largest and is 90 degrees.

Moving the magnetic field

With the passage of time, the arrangement of the magnetic poles changes.

Initially, the magnetic pole was opened in 1831, and then it was located hundreds of kilometers from its current location. The approximate distance traveled in a year is 15 km.

In recent years, the rate of movement of magnetic poles has increased. The North Pole moves at a speed of 40 km per year.

Permutation of magnetic fields

The process of changing polarities on Earth is called inversion. Scientists know, at least, about 100 cases, when the geomagnetic field changed its polarity.

It is believed that the inversion occurs every 11-12 thousand years. Other versions are called 13, 500 and even 780 thousand years. Perhaps the inversion does not have a clear periodicity. Scientists believe that under previous inversions, life on Earth continued.

People ask themselves the question: "When will we wait for the next change in polarity?"

The pole shift phase occurs during the last century. The South Pole is now located in the Indian Ocean, while the northern pole is moving across the Arctic Ocean towards Siberia. The magnetic field near the poles is weakened. The tension decreases.

Most likely, with the next inversion life on Earth will continue. The only question is, what price. If the inversion occurs with the extinction of the magnetosphere on Earth for a short time, it can be very dangerous for mankind. An unprotected planet is exposed to the adverse effects of cosmic rays. In addition, a decrease in the ozone layer can also be a serious hazard.

The change of poles to the Sun, which occurred in 2001, did not lead to the disconnection of its magnetic layer. Will there be such a scenario on Earth, scientists are not known.

Perturbation of the Earth's magnetosphere: effects on humans

At the initial approximation, the solar plasma does not reach the magnetosphere. But under certain conditions, the permeability of the plasma is disrupted, and the magnetic shell is damaged. The solar plasma and its energy penetrate into the magnetosphere. Regarding the rate of arrival of energy flows, there are three options for the response of the magnetosphere:

1. A calm state of the magnetosphere-the shell does not change its state, since the velocity of energy transfer is too small or equal to the amount of scattered energy inside the magnetic sphere.
2. Magnetic substorm. The state that arises when the velocity of incoming energy is higher than the rate of stationary dissipation, and some of the energy escapes from the magnetosphere through a channel called a substorm. The process consists in releasing part of the magnetospheric energy. Its brightest embodiment is the polar glow. Emissions of excess energy can occur with a frequency of 3 hours in the polar regions of both hemispheres.
3. A magnetic storm is the process of the strongest excitement of the field due to the high speed of energy coming from outside. The magnetic field undergoes changes also at the bottom, in the region of the equator.

The magnetic field of the Earth during the substorm changes locally, and during the storms the changes are global. In any case, these changes do not exceed a few percent, which is much less than man-made fields.

Medicine believes that magnetic storms adversely affect human health. During this period, the number of patients suffering from cardiovascular pathologies, depression and other neuropsychic disorders increases.

Great is the role of the Earth's magnetosphere in all geographic processes on the planet. This protective shell protects our planet from many unfavorable processes and affects weather conditions. Under the influence of changes in the magnetosphere, the climate changes, the life forms of animals and plants, and much more change on the Earth.