The magnetosphere envelops any body with a magnetic field. It appears due to the fact that particles with charges deviate from the original line of motion under the influence of internal magnetism. The meeting point of solar energy and the magnetic field forms the plasma that covers the magnetospheric shell.
Influence of the Sun on the Earth
The sun emits a large amount of energy, which is constantly expanding, "evaporating" outward. This expansion is called the solar wind.
The solar wind spreads in all directions, filling all interplanetary space. For this reason, a plasma formation called the solar wind plasma forms in the interstellar region.
Solar plasma moves in a spiral, on average over 4 days overcomes the interval between the Sun and the Earth.
The sun releases energy, thanks to which life continues on Earth. However, dangerous radiation also comes from the Sun, which is 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 from the radiation of the solar flux;
- an ionosphere that absorbs X-rays and ultraviolet radiation;
- the ozone layer, which holds back residual amounts of ultraviolet radiation.
As a result, the Earth's biosphere (the habitat of living organisms) is completely protected.
Earth's magnetosphere is a protective layer, the furthest from the center of the planet. It is a barrier to solar wind plasma. For this reason, the solar 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:
- cores;
- robes;
- Earth's crust.
There are various fields around the planet, including gravitational and magnetic. Gravity in its simplest sense is the attraction of the earth for all material particles.
Earth's magnetism lies in the phenomena occurring at the boundaries of the core and mantle. The planet itself is a huge magnet, a uniformly magnetized ball.
The cause of every magnetic field is electric current or continuous magnetization. Scientists dealing with the problem of Earth's magnetism find out:
- reasons for magneticgravity of the Earth;
- establish connections between terrestrial magnetism and its sources;
- determine the distribution and direction of the magnetic field on the planet.
These studies are carried out through magnetic surveys, as well as through observations in observatories - special points in different regions of the globe.
How does the magnetosphere work?
The type and structure of the magnetosphere are being developed:
- solar wind;
- earth magnetism.
The solar wind is the output of plasma, which is distributed from the Sun in any direction. The wind speed at the earth's surface is 300-800 km/s. The solar wind is filled with protons, electrons, alpha particles and is characterized by quasi-neutrality. The solar wind is endowed with solar magnetism, transported by plasma very far.
Earth's magnetosphere is a rather complex cavity. All its sections are filled with plasma processes, in which the mechanisms of particle acceleration are of great importance. On the sunny side, the gap from the center to the boundaries of the Earth is determined by the strength of the solar wind and can reach from 60 to 70 thousand kilometers, which is equal to 10-12 Earth radii Re. Re equals 6371 km.
The boundaries of the magnetosphere are different depending on the location in relation to the Sun. A similar border on the sunny side is similar in shape to a projectile. 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 end is unknown.
In the magnetospherethere are areas with high energy particles, they are called "radiation belts". The magnetosphere is capable of initiating various oscillations and is itself a source of radiation, some of which can penetrate the Earth.
Plasma leaks into the Earth's magnetosphere through intervals between the features of the magnetopause - polar cusps, as well as due to hydromagnetic phenomena and instabilities.
Magnetic field activity
Earth's magnetosphere affects geomagnetic activity, geomagnetic storms and substorms.
She protects life on Earth. Without her, life would stop. According to scientists, the oceans of Mars and its atmosphere have gone into space due to the undisguised influence of the solar wind. In the same way, the waters of Venus were carried away into outer space by a solar stream.
Jupiter, Uranus, Saturn and Neptune also have a magnetosphere. Mars and Mercury have small magnetic shells. Venus does not have it at all, the solar wind is managed thanks to the ionosphere.
Field Features
The main property of a magnetic field is its intensity. Magnetic intensity is a vector quantity. The magnetic field of the planet is depicted using lines of force, tangents to them show the direction of the intensity vector.
The magnetic field today is 0.5 oersted or 0.1 a/m. Scientists allow fluctuations in magnitude in the past. But for the last 2-3.5 billion years, the geomagnetic field has not changed.
Points on Earth where tension is vertically directed are called magnetic poles. There are two on Earth:
- North;
- Southern.
A straight line passes through both poles - the magnetic axis. The circle perpendicular to the axis is the magnetic equator. The field strength at the equator is horizontal.
Magnetic poles
Magnetic poles do not correspond to the usual geographic ones. The 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 is preserved.
The compass needle points exactly to the magnetic north pole. Magnetic observatories measure the fluctuations of the magnetic field during the day, some of them are engaged in every second measurement.
Magnetic meridians run from the North Pole to the South Pole. The angle between the magnetic and geographic meridian is called magnetic declination. Any point on earth has its own declination angle.
At the equator, the arrow of the magnet is placed horizontally. When moving north, the upper end of the arrow rushes down. The angle between the pointer and the horizontal surface is the magnetic inclination. In the region of the poles, the inclination is greatest and amounts to 90 degrees.
Movement of the magnetic field
The location of the magnetic poles changes over time.
Initially, the magnetic pole was discovered in 1831, and then it was located hundreds of kilometers from the current location. Approximate travel distance per year is 15 km.
In recent years, the pace of movement of the magnetic poles has been increasing. The North Pole is movingspeed of 40 km per year.
Changing magnetic fields
The process of changing polarities on Earth is called inversion. Scientists know of at least 100 cases where the geomagnetic field reversed its polarity.
It is believed that the inversion occurs once 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 during previous inversions, life on Earth was preserved.
People are wondering, "When is the next polarity reversal?"
The pole shift phase has been happening over the past century. The South Pole is now located in the Indian Ocean, while the North Pole is moving across the Arctic Ocean towards Siberia. The magnetic field near the poles weakens in this case. Tensions are easing.
Most likely, with the next inversion, life on Earth will continue. The only question is at what cost. If the inversion occurs with the extinction of the magnetosphere on Earth for a short time, it can be very dangerous for humanity. An unprotected planet is exposed to the adverse effects of cosmic rays. In addition, the depletion of the ozone layer can also pose a serious danger.
The change of poles on the Sun, which occurred in 2001, did not lead to the shutdown of its magnetic layer. Whether there will be a similar scenario on Earth, scientists do not know.
Disturbance of the earth's magnetosphere: impact on humans
At the initial approach, the solar plasma does not reach the magnetosphere. But under certain conditionsthe permeability of the plasma is disturbed, damage to the magnetic shell occurs. Solar plasma and its energy penetrate the magnetosphere. Regarding the rate of energy flows, there are three options for the response of the magnetosphere:
- Quiet state of the magnetosphere - the shell does not change its state, since the speed of energy movement is too low or equal to the amount of dissipated energy inside the magnetic sphere.
- Magnetic substorm. A state that occurs when the rate of incoming energy is higher than the rate of stationary dissipation, and part 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 personification is the aurora borealis. Emissions of excess energy can occur at intervals of 3 hours in the polar regions of both hemispheres.
- Magnetic storm is the process of the strongest disturbance of the field due to the high speed of energy coming from outside. The magnetic field is also changing below, in the region of the equator.
The Earth's magnetic field changes locally during substorms, while changes are global during storms. In any case, these changes are not higher than a few percent, which is much less than man-made fields.
Medicine believes that magnetic storms adversely affect human he alth. During this period, the number of patients suffering from cardiovascular pathologies, depression and other neuropsychiatric disorders increases.disorders.
Great is the role of the Earth's magnetosphere in all geographic processes on the planet. This protective shell protects our planet from many adverse processes and affects weather conditions. Under the influence of changes in the magnetosphere on Earth, climatic features, forms of life of animals and plants, and much more are changing.
