What generates the earth's magnetic field. How does the earth's magnetic field arise?

The Earth's magnetic field is similar to that of a giant permanent magnet tilted at an angle of 11 degrees to its axis of rotation. But there is a nuance here, the essence of which is that the Curie temperature for iron is only 770°C, while the temperature of the Earth’s iron core is much higher, and only on its surface is about 6000°C. At such a temperature, our magnet would not be able to retain its magnetization. This means that since the core of our planet is not magnetic, terrestrial magnetism has a different nature. So where does the Earth's magnetic field come from?

As is known, magnetic fields surround electric currents, so there is every reason to assume that the currents circulating in the molten metal core are the source of the earth’s magnetic field. The shape of the Earth's magnetic field is indeed similar to the magnetic field of a current-carrying coil.

The magnitude of the magnetic field measured on the Earth's surface is about half a Gauss, while the field lines seem to come out of the planet from the south pole and enter its north pole. At the same time, over the entire surface of the planet, magnetic induction varies from 0.3 to 0.6 Gauss.

In practice, the presence of a magnetic field on the Earth is explained by the dynamo effect arising from the current circulating in its core, but this magnetic field is not always constant in direction. Rock samples taken in the same places, but having different ages, differ in the direction of magnetization. Geologists report that over the past 71 million years, the Earth's magnetic field has rotated 171 times!

Although the dynamo effect has not been studied in detail, the Earth's rotation certainly plays an important role in generating currents that are believed to be the source of the Earth's magnetic field.

The Mariner 2 probe, which examined Venus, discovered that Venus does not have such a magnetic field, although its core, like the Earth's core, contains enough iron.

The answer is that the period of rotation of Venus around its axis is equal to 243 days on Earth, that is, the dynamo generator of Venus rotates 243 times slower, and this is not enough to produce a real dynamo effect.

By interacting with particles of the solar wind, the Earth's magnetic field creates conditions for the appearance of so-called auroras near the poles.

The north side of the compass needle is the magnetic north pole, which is always oriented towards the geographic north pole, which is practically the magnetic south pole. After all, as you know, opposite magnetic poles attract each other.

However, the simple question is “how does the Earth get its magnetic field?” - still does not have a clear answer. It is clear that the generation of a magnetic field is associated with the rotation of the planet around its axis, because Venus, with a similar core composition, but rotating 243 times slower, does not have a measurable magnetic field.

It seems plausible that from the rotation of the liquid of the metallic core, which constitutes the main part of this core, the picture arises of a rotating conductor, creating a dynamo effect and working like an electrical generator.

Convection in the liquid of the outer part of the core leads to its circulation relative to the Earth. This means that the electrically conductive material moves relative to the magnetic field. If it becomes charged due to friction between the layers in the core, then the effect of a coil with current is quite possible. Such a current is quite capable of maintaining the Earth's magnetic field. Large-scale computer models confirm the reality of this theory.

During the 1950s, as part of the Cold War strategy, US Navy vessels towed sensitive magnetometers along the ocean floor while they searched for a way to detect Soviet submarines. During the observations, it turned out that the Earth's magnetic field fluctuates within 10% in relation to the magnetism of the seabed rocks themselves, which had the opposite direction of magnetization. The result was a picture of reversals that occurred up to 4 million years ago, this was calculated by the potassium-argon archaeological method.

Andrey Povny

A team of scientists led by Simon Anzellini made a new discovery. During some experiments, they established new qualities of the solid part of the earth's core

Scientists have found that the iron core of the earth is heated to 6 thousand degrees Celsius, and this information is a thousand degrees higher than previously thought. And this fact now allows us to understand the nature of the magnetic field of our planet.

Simon Ancellin, a member of the French Commissariat for Atomic Energy in Grenoble, and his colleagues were able to calculate the temperature of the Earth's iron core by observing the behavior of iron under ultra-high pressure.

A group of scientists used their own method to determine the properties of iron. A piece of iron was placed inside a diamond anvil and compressed under a pressure of 2.2 million atmospheres, and then heated by a laser beam to 4.5 thousand degrees Celsius.

The experiment was carried out to obtain data that will help scientists determine the temperature of the solid part of the earth's core, in which the pressure reaches 3.3 million atmospheres. To the surprise of scientists, the temperature in the core reached 6-6.5 thousand degrees Celsius, which exceeds earlier ideas by a thousand degrees. As scientists say, the new discovery fits well into the general understanding of scientists about the nature and structure of the planet. And it allows us to explain the cause of the Earth’s magnetic field.

Source of the Earth's magnetic field

The history of the study of the issue of terrestrial magnetism begins in 1600, when the work of William Gilbert, the court physician of the English Queen Elizabeth I, was published, and it was called “On the Magnet, Magnetic Bodies and the Great Magnet - the Earth.” The essence of the work is that the scientist comes to the conclusion that the Earth is a large dipole magnet.

Until the 17th century, this work was the main work on geomagnetism. From the 17th to the 20th centuries, many studies and observations began to take place, which led scientists to new conclusions and properties. At this time, the work of such scientists as Halley Halley, Alexander von Humboldt, Joseph Gay-Lussac, James Maxwell, Carl Gauss is celebrated.

The formation of the theory of electromagnetism by Maxwell in the 70s of the 19th century is quite significant. From his equations it turns out that the magnetic field is formed by electric current. Consequently, this leads to the equivalence of closed elementary currents and magnetic dipoles, the moment of which is also called the magnetic moment of the current. When added, these quantities form, say, the magnetic field of a cylindrical magnet, which is approximately equal to the field of a solenoid of the same length and the same cross-section.

But at the moment, there was no clear idea of ​​where the Earth's magnetic field comes from. Modern scientific works on the nature of geomagnetism indicate the following: “Now, turning to the “big magnet,” the matter at first glance is not so difficult: to find in the middle of the planet current systems of the required configuration and forces that form a field on the Earth’s surface, the structure of which we have studied well. When we head into the Earth, then, having passed the crust, the upper mantle and the lower mantle, we will reach a huge liquid core, the existence of which was determined in the mid-20th century by Harold Jeffreys of the University of Cambridge. The actual liquid state of a large part of the core provides the conclusion of the mechanism for generating the geomagnetic field. The point is that the permanent magnetic field of the Earth is formed by electric currents that appear during the movement of a conducting fluid in the core. Another theory on this issue has not yet been invented.

When we go further and try to understand the essence of the processes of generating the Earth’s geomagnetic field, then it’s time to use the dynamo mechanism for this purpose. In short, we will assume that the formation of a magnetic field in the outer liquid core of the Earth is carried out in the same way as in a self-excited dynamo, where a coil of wires rotates in an external magnetic field. Consequently, due to electromagnetic induction, an electric current arises in the coil and forms its own magnetic field. It increases the external magnetic field, and the current in the coil also increases.

Naturally, the liquid core of the planet is not a dynamo. But when thermal convection appears in a liquid conductor, a certain system of flows of electrically conductive liquid is formed, which is consonant with the movement of the conductor. It would not be gross violence against nature to assume the existence of certain seed magnetic fields in the nucleus. Consequently, if a liquid conductor, during its relative motion, crosses the lines of force of these fields, then an electric current is formed in it, creating a magnetic field, which increases the external seed field, and this, in turn, increases the electric current and so on, like the song about the pope and his dog, who carelessly ate a piece of meat. The process will continue until a stationary magnetic field is established, when various dynamic processes balance each other."

The earth's magnetic field is the energy of the future

Those who are interested in the history of science and technology certainly know about Tesla's electric car. As historiographical reports state, this car moved thanks to an electric motor, and it drew energy from the space around it. Developers of space systems have long been trying to find its practical application.

Russian scientist Candidate of Physical and Mathematical Sciences Evgeny Timofeev, an employee of RSC Energia, has been working on this problem for many years. He has already managed to create a prototype of such a generator that would generate energy from the Earth's magnetic field. The generator works like this: when the device is set in motion, a sensitive voltmeter registers the occurrence of electromotive force in the circuit. The inventor clarifies that the method of operation of the device is based on the intersection of the Earth's magnetic field with a solenoid, some part of the winding of which is protected by a magnetic shield.

As the scientist states, in terms of practical use of the energy of sunlight, humanity is already much further ahead than the use of the Earth's magnetic field. In some aspects we are at the same level Tesla was at 75 years ago.

Such a phenomenon as magnetism has been known to mankind for a very long time. It got its name from the city of Magnetia, which is located in Asia Minor. It was there that a huge amount of iron ore was discovered. We can find the very first mentions of unique ones in the works of Titus Lucretius Cara, who wrote about this in the poem “On the Nature of Things”, approximately in the 1st century BC.

Since ancient times, people have found use for the unique properties of iron ore. One of the most common devices whose action was based on the attraction of metals was the compass. Now it is very difficult to imagine various industries that would not use simple magnets and electromagnets.

The Earth's magnetic field is the area around the planet that protects it from the harmful effects of radioactive radiation. Scientists still argue about the origin of this field. But most of them believe that it arose due to the Center of our planet having a liquid external and solid internal component. During rotation, the liquid part of the core moves, charged electrical particles move and a so-called magnetic field is formed.

The Earth's magnetic field is also called the magnetosphere. The concept of “magnetism” is a comprehensive and global property of nature. At the moment, it is impossible to create a completely complete theory of solar and terrestrial gravity, but science is already trying to understand many things and it manages to give quite convincing explanations of various aspects of this complex phenomenon.

Recently, scientists and ordinary citizens have been greatly concerned about the fact that the Earth's magnetic field is gradually weakening its influence. It has been scientifically proven that over the past 170 years the magnetic field has been steadily weakening. This makes you think, since it is a certain kind of shield that protects the Earth and wildlife from the terrible radiation effects of the sun's rays. resists the flow of all such particles that fly towards the poles. All these flows linger in the upper layer of the atmosphere at the poles, forming a wonderful phenomenon - the northern lights.

If the Earth’s magnetic field suddenly disappears or weakens significantly, then everything on the planet will be under the direct influence of cosmic and solar radiation. In turn, this will lead to radiation diseases and damage to all living organisms. The consequence of such a disaster will be terrible mutations or complete death. To our great relief, such a development is unlikely.

Paleomagnetologists were able to provide fairly reliable data that the magnetic field is constantly oscillating, and the period of such oscillations varies. They also compiled an approximate curve of field fluctuations and found that at the moment the field is in a descending position and will continue to decline for another couple of thousand years. Then it will begin to intensify again over the course of 4 thousand years. The last maximum value of the magnetic field attraction occurred at the beginning of the current era. The reasons for such instability have been put forward in a variety of ways, but there is no specific theory on this matter.

It has long been known that many magnetic fields have a negative effect on living organisms. For example, experiments carried out on animals have shown that an external magnetic field can delay development, slow down cell growth and even change the composition of the blood. That is why they lead to a deterioration in the health of weather-dependent people.

For humans, a safe magnetic field of the Earth is a field with a strength value of no more than 700 oersteds. It is worth noting that we are not talking about the Earth’s magnetic field itself, but about the electromagnetic fields that are formed during the operation of any radio and electrical device.

The physical side of the process of the influence of the Earth’s magnetic field on humans is still not entirely clear. But we managed to find out that it affects plants: germination and further growth of seeds directly depend on their initial orientation in relation to the magnetic field. Moreover, its change can either accelerate or slow down the development of the plant. It is possible that someday this property will be used in agriculture.

Earth is the force of its gravity. It varies in some places, but the average is 0.5 oersted. In some places (in the so-called tension increases to 2E.

Bibliographic description: Korobko P. I., Frolova V. M., Lobanov I. A., Titova N. A., Panshina S. G., Panshin E. A. Using the Earth’s magnetic field in solving problems in the Far North // Young scientist. 2016. No. 5. P. 62-68..06.2019).



For most territories of the Far North, the only possible method of transport is by plane. During the summer navigation season, sea traffic is used only for the delivery of goods. There is no passenger service due to the long length of sea routes. In principle, there are no railway or road connections with the “mainland”.

Another very pressing problem in the Far North is energy. If in other warmer regions of the country energy problems are successfully solved by the operation of hydroelectric power plants, then in areas adjacent to the coast of the Arctic Ocean, such an option loses its advantages (due to the freezing of rivers in winter), and in some places it is not feasible due to too small a height difference (necessary for the operation of a hydroelectric station).

The construction of fossil fuel power plants in conditions of a polar climate and permafrost is economically unjustified; their payback period is too long; in addition, oil and gas fields may be located at a considerable distance from places where electricity is required. Thus, fuel is transported to many coastal areas by sea.

It is obvious that the region's dependence on periodic fuel supplies and on irregular passenger and cargo traffic cannot allow the regions to develop to their full potential. This article proposes a technical solution for transport communication between the settlements of Salekhard - Anadyr, as well as methods for obtaining energy directly in areas in need, which will open up new prospects for the development of facilities located in the Far North.

Characteristics that the vehicle being developed must meet:

– use of renewable, safe, environmentally friendly and high-potential energy sources. In this case, preference should be given to a more expensive, but operating on the basis of renewable resources and environmentally friendly source of energy;

– use of the latest technologies and innovative solutions.

To implement this project, we conducted the following research:

– analysis of the geographical and climatic features of the territories through which the route “Anadyr - Salekhard” should run;

– analysis of the transport used on the territory of the proposed route;

– search for possible renewable energy sources.

Before starting to develop a technical solution for transport communication between the settlements of Salekhard - Anadyr, we analyzed the geographical and climatic features of the territories through which the Anadyr - Salekhard route should run. Briefly, we can say that the cities of Anadyr and Salekhard are located at approximately the same geographical latitude. The likely route runs through the polar zone with a subarctic climate. This territory is part of the aurora zone. A small influx of solar radiation, flat terrain, open to the invasion of air masses from the Arctic in the summer and supercooled continental masses in the winter, determine the sharp continentality and severity of the climate.

Permafrost, an abundance of swamps, lakes and rivers. Long winters, short cool summers, strong winds, insignificant snow cover - all this contributes to freezing of the soil to a great depth.

An analysis of the transport used on the territory of the proposed route showed that due to unstable weather prone to rain, snowfall and strong winds, aircraft flights may be delayed or completely cancelled. During certain periods in spring and autumn, planes do not fly at all. The existing sea communication during the summer navigation season is used only for the delivery of goods. There is no passenger service due to the long length of sea routes. In principle, there are no railway or road connections with the “mainland”.

Our group carried out an analysis of the latest achievements of science and technology in the field of transport and the use of new types of energy that can be used to implement the project.

More recently, at the end of the last century (1986), a new type of superconductor was discovered that did not require very low temperatures; at that time, the known superconductors - mercury and lead - acquired superconducting properties at temperatures down to -270 ° C. Currently, ceramic conductors acquire superconducting properties at temperatures from -191°C to -183°C. This temperature can be maintained using liquid nitrogen (it is formed at a temperature of -195.75°C). This discovery dramatically reduced the cost of superconductors.

This discovery will make it possible to create powerful supermagnets that hold vehicles like trains in the air.

To set a magnetic levitation train in motion, a jet of compressed air is sufficient to overcome the force of air resistance.

But to use liquid nitrogen, refrigeration equipment is required. And for the operation of refrigeration equipment, a source of energy is required. Where can I get it in the tundra? A source of energy is required.

Search for energy sources.

When considering the climatic and geographical features of the territory of the proposed route, we found out that the route is located in the zone of auroras.

The aurora is the most magnificent phenomenon that a person can observe on Earth. But the aurora is not only a grandiose and beautiful spectacle. It is the only manifestation of the impact of solar radiation on near-Earth space and the earth's atmosphere that can be seen with the naked eye.

Aurora is the glow of the earth's atmosphere under the influence of streams of solar particles that invade the atmosphere.

Solar streams approaching the Earth flow around it, since the Earth is protected from these particles by its own magnetic field. However, the configuration of the Earth's magnetic field is such that some of these particles penetrate into the magnetosphere, and from it into the upper atmosphere. Possessing a large amount of energy and penetrating into the Earth's atmosphere, these particles collide with atoms and molecules of the upper atmosphere causing its glow.

The aurora can be compared to the Firebird from folk legends and fairy tales. It turns out that our scientists have already figured out how to catch this Firebird by the tail. And if we use this in this project, then we will give life to the unique invention of the Russian physicist N.P. Danilkin (“Institute of Applied Geophysics named after Academician E.K. Fedorov.” He invented a unique method for obtaining electrical energy from the upper layers of the atmosphere in the zone auroras, called the ionosphere.

The essence of the method is as follows.

It is planned to use the possibility of extracting electrical energy from the ionosphere, where currents flow at altitudes of more than 100 km above the Earth's surface. Such a power plant should be located on the surface of the Earth and will draw energy from near-Earth space, using the transformation of electromagnetic energy, which is a consequence of the work of forces of a planetary nature, into electric current for technical purposes.

It turns out that the main “pumping” of energy along the chain of solar-terrestrial connections occurs as a result of solar flares, which are accompanied by magnetic storms. However, in the aurora zone and in a calm state, and even more so during periods of magnetic storms, the magnetic field strength on the Earth's surface undergoes continuous changes.

Therefore, if a single-wire circuit is placed on the surface of the Earth, then in such a circuit during the period of change in the magnetic field strength, in accordance with the laws of physics, an electromotive force arises, causing an electric current.

The total power of currents constantly flowing in the Earth's ionosphere significantly exceeds the needs of humanity. If you learn how to connect to these currents technologically competently, then the whole process will turn out to be environmentally friendly and safe.

In order to increase the power of such a power plant, the required number of circuits can be connected in parallel to this circuit.

There is also a way to reduce the electrical resistance of the circuit by using the phenomenon of superconductivity.

Of course, before building power plants and laying an overpass for a magnetic levitation train, it is necessary to carry out a lot of serious calculations, experiments and development work. Despite this, there are already facts proving the technological feasibility and potential of such a power plant. For example, this is well illustrated by the events that happened in the province of Quebec (Canada) on March 13–14, 1989. At this time, after a powerful flare on the Sun and the passage of a large charge of energy through a chain of processes on the Sun-Earth line, the characteristics of the electromagnetic induction field in this zone turned out to be located in such a way that strong induction currents arose in high-voltage power lines. Moreover, the power of these currents turned out to be such that the fuses turned off 40% of the power of the entire Hydro-Quebec power system, which amounted to 9 GW. Note that these powerful induction currents arose in a system that was not oriented toward receiving them!

Another famous event occurred on September 1–2, 1859. It was the most powerful geomagnetic storm in recorded history. A complex of events that includes both a geomagnetic storm and the powerful active phenomena on the Sun that caused it is sometimes called the “Carrington Event.”

From August 28 to September 2, numerous spots and flares were observed on the Sun. Just after noon on September 1, British astronomer Richard Carrington observed the largest flare, which caused a large release of mass of solar radiation. It rushed towards the Earth and reached it in 18 hours, which is very fast, since this distance is usually covered by the ejection in 3-4 days. The ejection moved so quickly because previous ejections had cleared the way for it. The largest geomagnetic storm in recorded history began, causing the failure of telegraph systems throughout Europe and North America. Northern lights have been observed all over the world, even over the Caribbean;

As a result, on September 1 and 2, 1859, the entire telegraph system in North America and throughout Europe failed: transmission lines sparked, telegraph paper spontaneously ignited, and some devices, such as the telegraph, calmly continued to operate, having already been disconnected from the power source.

From the calculations of the Russian physicist N.P. Danilkin (Institute of Applied Geophysics named after Academician E.K. Fedorov), two conclusions can be drawn:

– the proposed method is capable of extracting electricity sufficient for industrial purposes from the ionosphere;

– the ionosphere and magnetosphere have sufficient energy reserves for these purposes.

The main disadvantages of this method of generating energy at the level of modern technology are the very impressive size of the operating circuit and the obvious high cost of its creation. However, the advantages of the method may outweigh these disadvantages, especially if new materials convenient for solving this problem are discovered.

The advantages of this power plant include:

– such a station, once built, will not wear out and theoretically will function as long as the Sun shines and the “Sun-Earth” chain of connections operates;

– the technological process of extracting energy from the ionosphere turns out to be environmentally friendly and safe, and there is not even a theoretical possibility of causing a catastrophe.

Conclusion.

Experimental confirmation of the developed project in laboratory conditions.

In order to obtain experimental confirmation of the idea of ​​​​producing electricity from the ionosphere, it is enough to carry out the experiment demonstrated in the school physics course.

Having completed this experiment, we examined what the phenomenon of electromagnetic induction is. For the experiment, we needed a galvanometer, a permanent magnet and a coil with wire wound on it. The ends of the wire were connected to the coil. When we pushed a permanent magnet inside the coil, the galvanometer deflected. This means that an electric current has arisen in the circuit.

Since we do not have any current source in the circuit, it is logical to assume that the current arises due to the appearance of a magnetic field inside the coil. When we pull the magnet back out of the coil, we will see that the galvanometer readings will change again, but its needle will deviate in the opposite direction. We again received a current, but this time directed in the other direction.

Rice. .1 The phenomenon of electromagnetic induction

After this, we performed a similar experiment with the same elements, only in this case we fixed the magnet motionless. Now we removed and put on the magnet the coil itself, connected to the galvanometer. As a result, we received similar events. Deflecting, the galvanometer needle showed us the appearance of current in the circuit. At the same time, when the magnet was stationary, there was no current in the circuit - the needle stood at zero.

Rice. 2. Conducting a project experiment in laboratory conditions

The coil can be replaced with a conducting circuit and experiments can be done on moving and rotating the circuit itself in a constant magnetic field, or a magnet inside a stationary circuit. The results will be the same - the appearance of current in the circuit when the magnet or circuit moves.

Thus, the experiment conducted allows us to conclude:

With any change in the magnetic flux penetrating the circuit of a closed conductor, an electric current arises in this conductor. In this case, the electric current exists in during the entire process of changing the magnetic flux.

The same principle is used in the method of generating electricity from the ionosphere. Our planet Earth is a huge magnet with a constant magnetic field. Due to the impact of solar radiation on our planet, the Earth's magnetic field undergoes constant changes. Particularly large values ​​of magnetic field variations are observed in the aurora zone. Magnetic storms and substorms can often be observed there.

Description of the technical solution.

After carrying out the planned studies, the following decision was prepared:

Transport connecting the two regions in the Far North should be a comfortable magnetic levitation train using the latest generation of superconductors. If it is not possible to practically implement the idea of ​​​​using superconductors, use the property of repulsion of magnet poles of the same name.

Rice. 3. Project diagram

1) The energy required to power the overpass and magnetic levitation train is obtained using the method of generating electricity from the ionosphere. In addition, powerful wind generators can be placed along the entire route and the energy of strong winds in these places can be used.

2) If the platform from which the train is to depart is installed at an altitude of 400 meters, and then the road along which the magnetic levitation train will slide is laid downhill, then by the time it reaches Earth level the train will have a speed of about 310 km/h. Approaching the destination station, the road along which the train is moving will slowly begin to rise to 400 m. And at the arrival point the train will stop. If it does not have enough speed in any section, the train will be given the required speed using a jet of compressed air.

Rice. 4. Departure and arrival platform diagram

Execution plan for the proposed project.

To implement the project it is necessary:

1) Conducting research work on the development of magnetic levitation transport using electrical energy obtained from the upper layers of the atmosphere in the aurora zone, called the ionosphere (the period of completion of the work, according to experts, is 2-3 years);

2) Conducting development work to create a magnetic levitation vehicle using electrical energy obtained from the upper layers of the atmosphere in the aurora zone, called the ionosphere. Result of the work: a prototype of a road section with a magnetic levitation train using electricity obtained from the upper layers of the atmosphere in the aurora zone, called the ionosphere (the work period is estimated by experts to be 5–7 years).

– implementation of the project on the Anadyr-Salekhard section. (work completion period, according to specialists, is 25–30 years).

Performance assessment andeffectiveness.

Conclusion

On Earth there is an alternative, environmentally friendly and renewable source of planetary electromagnetic energy, continuously replenished by processes originating in the Sun and coming to the Earth along a chain of solar-terrestrial connections. The modern technological level makes it possible to use this energy.

Disadvantages of the project

– impressive size

- the high cost of its creation.

Advantages of the project:

– wear resistance of the power plant;

– an inexhaustible source of energy (Sun);

– environmental friendliness;

– profitability due to free electricity;

– having such a source of electricity, it is possible to develop infrastructure throughout the territory where the train overpass lies.

– prospects for the development of new territories.

Literature:

1. Kaku M. Physics of the future. Translation from English. Moscow 2014;
2. Danilkin N.P. “On the possibility of obtaining electrical energy from the ionosphere” “Electricity”. 1996, no. 4, p. 71–75;
3. Dmitriev A. N., Shitov A. V., Technogenic impact on the natural processes of the Earth. Gorno-Altaisk, 2001 p. 9;
4. Dokumentika.org [Electronic resource]. - Access mode: http://dokumentika.org/zemli/solnechnaya-burya-1859-goda.

The Earth's magnetic field is a formation generated by sources inside the planet. It is the object of study in the corresponding section of geophysics. Next, let's take a closer look at what the Earth's magnetic field is and how it is formed.

general information

Not far from the Earth's surface, approximately at a distance of three of its radii, the lines of force from the magnetic field are located along a system of “two polar charges”. There is an area called the "plasma sphere" here. With distance from the surface of the planet, the influence of the flow of ionized particles from the solar corona increases. This leads to compression of the magnetosphere on the side of the Sun, and, on the contrary, the Earth’s magnetic field is stretched on the opposite, shadow side.

Plasma Sphere

The directional movement of charged particles in the upper layers of the atmosphere (ionosphere) has a noticeable effect on the Earth's surface magnetic field. The location of the latter is one hundred kilometers and above from the surface of the planet. The Earth's magnetic field holds the plasmasphere. However, its structure strongly depends on the activity of the solar wind and its interaction with the confining layer. And the frequency of magnetic storms on our planet is determined by flares on the Sun.

Terminology

There is a concept "magnetic axis of the Earth". This is a straight line that passes through the corresponding poles of the planet. The "magnetic equator" is the large circle of the plane perpendicular to this axis. The vector on it has a direction close to horizontal. The average strength of the Earth's magnetic field is significantly dependent on geographic location. It is approximately equal to 0.5 Oe, that is, 40 A/m. At the magnetic equator, this same indicator is approximately 0.34 Oe, and near the poles it is close to 0.66 Oe. In some anomalies of the planet, for example, within the Kursk anomaly, the indicator is increased and amounts to 2 Oe. Field lines of the Earth’s magnetosphere with a complex structure , projected onto its surface and converging at its own poles, are called “magnetic meridians”.

Nature of occurrence. Assumptions and conjectures

Not long ago, the assumption about the connection between the emergence of the Earth’s magnetosphere and the flow of current in the liquid metal core, located at a distance of a quarter to a third of the radius of our planet, gained the right to exist. Scientists also have an assumption about the so-called “telluric currents” flowing near the earth’s crust. It should be said that over time there is a transformation of formation. The Earth's magnetic field has changed several times over the past one hundred and eighty years. This is recorded in the oceanic crust, and this is evidenced by studies of remanent magnetization. By comparing areas on both sides of the ocean ridges, the time of divergence of these areas is determined.

Earth's magnetic pole shift

The location of these parts of the planet is not constant. The fact of their displacements has been recorded since the end of the nineteenth century. In the Southern Hemisphere, the magnetic pole shifted by 900 km during this time and ended up in the Indian Ocean. Similar processes are taking place in the Northern part. Here the pole moves towards a magnetic anomaly in Eastern Siberia. From 1973 to 1994, the distance by which the site moved here was 270 km. These pre-calculated data were later confirmed by measurements. According to the latest data, the speed of movement of the magnetic pole of the Northern Hemisphere has increased significantly. It grew from 10 km/year in the seventies of the last century to 60 km/year at the beginning of this century. At the same time, the strength of the earth's magnetic field decreases unevenly. So, over the past 22 years, in some places it has decreased by 1.7%, and somewhere by 10%, although there are also areas where it, on the contrary, has increased. The acceleration in the displacement of the magnetic poles (by approximately 3 km per year) gives reason to assume that their movement observed today is not an excursion, but another inversion.

This is indirectly confirmed by the increase in the so-called “polar gaps” in the south and north of the magnetosphere. Ionized material from the solar corona and space rapidly penetrates into the resulting expansions. As a result, an increasing amount of energy is collected in the circumpolar regions of the Earth, which in itself is fraught with additional heating of the polar ice caps.

Coordinates

In the science of cosmic rays, geomagnetic field coordinates are used, named after the scientist McIlwain. He was the first to propose the use of them, since they are based on modified versions of the activity of charged elements in a magnetic field. For a point, two coordinates are used (L, B). They characterize the magnetic shell (McIlwain parameter) and field induction L. The latter is a parameter equal to the ratio of the average distance of the sphere from the center of the planet to its radius.

"Magnetic inclination"

Several thousand years ago, the Chinese made an amazing discovery. They found that magnetized objects can be positioned in a certain direction. And in the middle of the sixteenth century, Georg Cartmann, a German scientist, made another discovery in this area. This is how the concept of “magnetic inclination” appeared. This name refers to the angle of deviation of the arrow up or down from the horizontal plane under the influence of the planet’s magnetosphere.

From the history of research

In the region of the northern magnetic equator, which is different from the geographic equator, the northern end goes down, and in the southern, on the contrary, it goes up. In 1600, the English physician William Gilbert first made assumptions about the presence of the Earth's magnetic field, which causes a certain behavior of objects that were previously magnetized. In his book, he described an experiment with a ball equipped with an iron arrow. As a result of his research, he came to the conclusion that the Earth is a large magnet. The English astronomer Henry Gellibrant also conducted experiments. As a result of his observations, he came to the conclusion that the Earth's magnetic field is subject to slow changes.

José de Acosta described the possibility of using a compass. He also established the difference between the Magnetic and North Poles, and in his famous History (1590) the theory of lines without magnetic deflection was substantiated. Christopher Columbus also made a significant contribution to the study of the issue under consideration. He was responsible for the discovery of the variability of magnetic declination. Transformations are made dependent on changes in geographic coordinates. Magnetic declination is the angle of deviation of the needle from the North-South direction. In connection with the discovery of Columbus, research intensified. Information about what the Earth's magnetic field is was extremely necessary for navigators. M.V. Lomonosov also worked on this problem. To study terrestrial magnetism, he recommended conducting systematic observations using permanent points (similar to observatories). It was also very important, according to Lomonosov, to do this at sea. This idea of ​​the great scientist was realized in Russia sixty years later. The discovery of the Magnetic Pole on the Canadian archipelago belongs to the polar explorer Englishman John Ross (1831). And in 1841 he discovered another pole of the planet, but in Antarctica. The hypothesis about the origin of the Earth's magnetic field was put forward by Carl Gauss. He soon proved that most of it is fed from a source inside the planet, but the reason for its minor deviations is in the external environment.