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Tension magnetic field

The tension of the magnetic field is one of the main values \u200b\u200bcharacterizing the magnetic field.

In the SSS system, the tension of the magnetic field is measured in Ersteda (E), in the System System - in amperes per meter (a / m). The technique of Ersted gradually displaces the unit of the SI ampere per meter.

1 e \u003d 1000 / (4p) car? 79,5775 a / m.

1 a / m \u003d 4p / 1000 er? 0,01256637 E.

In vacuum (or in the absence of a medium capable of magnetic polarization, as well as in cases where the last neglect) The voltage of the magnetic field (H) coincides with the magnetic induction vector (b) with an accuracy of the coefficient equal to 1 in the SGS and M0 in C.

It should be borne in mind that a more fundamental characteristic of the magnetic field is the magnetic induction vector of B. It is it that determines the validity of the magnetic field to the moving charged particles and currents, and can also be directly measured, while the voltage of the magnetic field H can be considered Rather, as an auxiliary value (although it is easier to calculate it, in a static case, it consists of its value: After all, H create so-called free currents that are relatively easy to directly measure, but difficult to measurable related Toki. - There are currents molecular, etc. - not necessary to consider).

The magnetic field strength can be determined by force that acts on the trial magnet placed in the field. Since the magnetic poles do not exist separately, the oppositely directed forces act on the northern and southern poles of the test magnet, and the moment a pair of forces arises. This moment characterizes the magnitude of the field strength in this place.

In a magnetic field of a cylindrical coil, it is directly proportional to the number of turns and the strength of the current and inversely proportional to the length of the coil. The direction of the magnetic field strength vector at each point coincides with the direction silest lines. Inside the coil (magnet), it is directed from the southern pole to the North, outside the coil - from the northern to the southern one.

The tension of the magnetic field is determined by the formula:

Magnetic Field Measurement Devices

All magnetometers can be functionally divided into two groups

Magnetometers for measuring external magnetic fields or otherwise, fields created by objects and magnetometers to study the magnetic properties of the substance. Despite the fact that the magnetometers included in the first and second groups are functionally different and constructively differ from each other, the same physical phenomena can be applied in them.

In this regard, consider the classification of magnetometers based on the laws underlying their work. They can be divided into five main groups:

· Furrosonda

· Magneticiducive

· Magnetically resistor,

· Quantum,

· On the Hall Effect.

Ferrorsonda magnetometers

Ferrorsonda magnetometers were invented at the beginning of the thirties simultaneously in Russia and Germany.

The basis of the operation of the ferro-ended magnetometer is taken a change in the magnetic properties of the ferromagnet when changing the magnetic field.

It is known that when magnetizing and subsequent reclamation of the ferromagnet on the chart

J \u003d f (h) where

J - magnetization of the ferromagnet,

H is the tension of the magnetic field, a closed figure is formed, which was called the hysteresis loop. In Figure JS and with H \u003d HS is called the magnetization of saturation. The magnetization of + jr and -jr with H \u003d 0 is called residual magnetization (which is necessary to create permanent magnets).

The tension + HC and -HC magnetic field, fully modified ferromagnet, is called coercive force. It characterizes the ability of the ferromagnet to maintain the magnetized state.

If you have a wire wire on a ferromagnetic rod or ring, such a winding is called an excitation winding, and to skip the variable sinusoidal current through it, then this current, creating its alternating field will enchain the ferromagnet with the frequency of the current.

However, if the rod or ring winding another winding, which is called the measuring winding, then in this winding will be induced by the EMF of mutually induction, as well as this happens in the transformer.

In the absence of an external magnetic field, i.e. With symmetrical with respect to the axis, the hysteresis loops in the secondary winding will appear EMF without distortion (in fig. 4 is indicated by the letter F).

However, if there is an external field, the axis of the ON will shift up or down, depending on the direction of the induction vector of the external field, is proportional to the magnitude of this field. (In fig. 2 OH axis shifted up).

In this case, with the reclamation of ferromagnet, the excitation current, with the same current amplitude, the ferromagnet will enjoy saturation.

Accordingly, the positive part of the signal will be distorted, Fig.5.

It will look like in the figure as cutting off the vertices of the sinusoidal signal, although the shape of the negative part of the EMF signal will not be distorted. Accordingly, if the vector induction vector of the external magnetic field is directed in the opposite direction, it will correspond on the shifting of the axis of the axis down. In this case, the negative part of the secondary coil is distorted. The magnitude of the distortion depends on the value of the induction of the external magnetic field. Thus, constructing an electronic circuit capable of analyzing the level of distortion, proportional to the external magnetic field, can be measured its value and determine the direction of the induction vector of the measured magnetic field.

magnetomer magnetic field tension

Furrorsonda magnetometers have great sensitivity, and in work stability, can measure fields up to tens of nanotela.

For the first time for measuring in space, a three-component ferrozond magnetometer was installed on board the moon space station10. Later, magnetic fields of Mars and Venus were investigated by improved ferro-ended magnetometers.

Magnetunductive magnetometers

The functional diagram of the magneto inductive magnetometer is shown in Fig. 6 a. The basis of the magnetometer is a stable high-risk oscillating circuit, which is included in the generator. The core of the inductance coil of the contour is made of ferromagnet. The change in the tension of the external magnetic field leads to a proportional change in the inductance of the coil and, accordingly, to change the frequency of the generator, Fig. 6b. Thus, measuring the signal frequency can be judged by the induction of the measured magnetic field.

The use of microprocessor equipment allows you to automate the process of measuring the magnetic field.

Such magnetometers are used as part of electronic compasses of marine courts.

Magnetic resistor sensors

The name of magnetic sensors speaks for itself. Resistive elements that are elements sensitive to the magnetic field first described the famous English physicist William Thomson (Lord Kelvin) in 1856, a little later Karl Friedrich Gakss. However, the phenomenon of change electrical resistance The material in the magnetic field is called the Gauss effect. The effect of resistance changes in the field is associated with the curvature of the trajectory of the movement of current carriers under the action of Lorentz's strength. This will lead to a decrease in current force, i.e. An increase in the resistance of the conductor.

In pure metals, the ratio of the change in resistance to the initial resistance value is slightly and amounts to the interests of the percent. In semiconductors it is more. For example, Germany is equal to three. The main semiconductor material for the manufacture of magnetic resistors is India Antimonide - InSB and India Arsenide INAS.

Reducing the resistance in the magnetic field is observed only in special alloys of metals with impurities of manganese, chromium, cobalt. The explanation of these effects was given by the Japanese physicist JUN Condo in 1964, by whose name is the effect.

To measure the field of magnetoresistors, the diagram of the measuring bridge is built, Fig. 7. Figure 8 shows a diagram of a measuring bridge made on a silicon plate as an integral chip.

All four incoming magnetically enabled modified their resistance when changing the measured magnetic field.

In this case, it should be paid to the fact that resistance changes in adjacent shoulders are opposed to the sign. When exposed to the magnetic field of one polarity, the change in resistors of resistors R1 and R3 occurs with one sign (minus), changing the resistors of resistors R2 and R4 with the opposite sign (plus). Such a bridge circuit makes it possible to increase the sensitivity of the magnetometer at least twice, under all equal conditions. Next, the output signal (voltage of the unbalance of the bridge) enters the linear amplifier input and then on the electronic circuit of processing the measured signal (not shown in the figure).

Currently, magnetic sensory sensors are produced by a series of American firms in the form of integrated circuits, for example, the KMZ10 series bridge. 7.

The domestic electronic industry produces MR type magnetorestors and a cm resistance from 50 to 200 ohms, with a capacity of 0.125 W and 0.25 W. The design of magnetometers, built on the basis of magnetic sensor sensors, is very simple and cheap, as well as easy to operate. They found use in devices for measuring the magnetic field of the Earth, incl. and navigation devices.

Quantum magnetometers

The principle of operation of quantum magnetometers is based on the quantum properties of charged particles interacting with the magnetic field. One of these properties is the precession of electrons in a homogeneous constant magnetic field, which was predicted in 1895 English physicist Joseph Larmore.

According to his arguments, the electron system of the electron system in the magnetic field retain its form if we assume that the reference system rotates around the direction of the magnetic field induction vector along with electrons, fig. 9C frequency:

sl \u003d EH / 2 MC,

where E and M is the charge and the mass of the electron,

H - magnetic field strength,

c is the speed of light.

In fig. 9 The black arrow shows the direction of the magnetic field intensity vector, and the red is the direction of the magnetic moment of the electrons.

This rotation of the magnetic moment vector of the electron around the magnetic field strength vector is similar to the rotation of the top (gyroscope), the name of the Laroric precession was called.

As it turned out later, Larmorova precession is characteristic not only for electrons, but also atoms, nuclei of atoms and protons, i.e. Charged particles located in a magnetic field and having a moment of moment of pulse. The Larmor precession is due to the action of the power of Lorentz acting on charged particles moving in a magnetic field. For example, the Larmor proton frequency in a magnetic field induction of 1 TL is 42 MHz.

In the proton magnetometer, the sensor serves a working substance, the molecules of which contain hydrogen atoms, for example, distilled water or benzene.

The working substance in the ampoule is placed inside the winding of the inductance L, which is supplied to the rectangular current pulse, which creates a magnetic field of the value of about H0 \u003d 10 mT, Fig. ten.

In a magnetic field of winding, the magnetic moments of protons take the same orientation and create a total total magnetic moment.

After the pulse is completed, the protons begin to precess in the measured magnetic field around the tension vector H. The synchronous precession of protons with a total magnetic moment induces in the same winding the EDC variable, the frequency of which is equal to the frequency of the proton precession. In the measured frequency induced in the EMF winding, the magnetic field induction is calculated from the formula.

It should be noted that the AMC amplitude is the tenths of the microvolt. In this regard, there are high requirements for an amplifier, which should increase the signal to millions of times and at the same time have a very low level of its own noise and linearity. The sensitivity of proton magnetometers can reach the tenths of the nanotela. Proton magnetometers have been widely used, both in the field of space research and in everyday life, as metal detectors.

Magnetometers on the Hall Effect

The Hall effect lies in the following: if the planing of semiconductor material is placed in a magnetic field, the vector of induction of which to perpendicular to the plane plane, and skip the current i, then on the side edges of the plate there is a difference in potentials - EMF Hall EX, directed perpendicular to vectors B and I

where RX is a permanent lounge determined by the material of the plate (Germany, arsenic indium, surmonevy indium, etc.) and d - plate thickness.

It follows from the equation that if i \u003d const, then ex \u003d f (b).

Devices that use the Hall Effect are used to measure the induction of both constant and variable magnetic fields in a wide range of frequencies. At the same time, they are trying to obtain EMF Hall of the variable, so that the AC amplifier can be used in the instrument diagram. To do this, when measuring the induction of a constant field through a plate (Hall transmitter) skip alternating current, When measuring the induction of an alternating field - permanent.

The Hall converter has a high sensitivity, small dimensions and independence EX from frequency in fairly wide limits (up to Hz). The disadvantages of the Hall converter should first include the dependence of its parameters from temperature. To reduce the effect of temperature, the Hall converter in some devices enter into a thermostat.

In order to increase the accuracy of measurement of the EMF Hall, it is always measured by the compensation method.

The Hall sensors usually use alloyed semiconductors with a predominance of a single sign charge, for example, India Arsenide single crystals - Inas, Gallium arsenide - GaAs, India Antimonide - INSB.

The advantages of the Hall sensors are their small sizes (1 mm2 or less) and a small mass, in connection with this, very small inertia, which allows them to use them at frequencies to Hz.

As a rule, before measuring the magnetic field, to establish a linear dependence of the value of the EMU Hall from the induction of the magnetic field, the Hall sensor is calibrated on the reference value of the magnetic field induction.

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\u003e Components of the magnetic field

Any point about the magnetic field vector of the magnetic field F (B), may be decomposed into components in various ways

In one case, these constituents will be F, or B, - the absolute value (module) of the vector - and two angles D and I. The angle D is formed by the direction to the north and the horizontal component of the vector B, I is the angle between B and N. D is considered positive If H is deflected to the east, I positively with deviation in down from the horizontal plane. The value of D is called magnetic flange and - with a outer. The vertical plane passing through H is called (local) the meridian plane.

In another case, x, y, z - northern (x) and eastern (y) components n and the vertical component z, which is considered positive, if it is considered to be positive, if it is considered to be positive if it is considered. The tension F (B), called "full force", n, z (horizontal and vertical component) and X, Y are measured in Gaussians or gamma; D and I are measured in arc degrees and minutes. All 7 values \u200b\u200bin, n, d, i, x, y, z are called magnetic elements. Among themselves they are associated with the following ratios:

N \u003d in cos i, z \u003d b sin i \u003d h tg i,

X \u003d h cos d, y \u003d h sin d,(1)

X. 2 + Y. 2 \u003d H. 2 , X. 2 + Y. 2 + Z. 2 \u003d H. 2 + Z. 2 \u003d B. 2 .

For a complete description AT three independent elements. If these elements are specified, any others can be obtained from the relation (1).

The usual compass arrow is balable, rotating horizontally on the vertical axis. The compass arrow, balanced to magnetization and capable of rotating in the plane of the magnetic meridian around the horizontal axis, is called a deposition saunas, or an inclinitor. In the northern hemisphere of the Earth almost everywhere the north pole of the magnetic arrow is directed down (I positively), in the southern hemisphere down the south pole arrows (I is negative). The areas of positive and negative I are separated by a line (called magnetic equator, or an equator of inclination), along which i \u003d 0. Magnetic arrow (balanced to magnetization) at any point on this curve is located horizontally.

At points where the horizontal component AT disappears, the magnetic arrow is installed vertically. These points are called the poles of magnetic inclination, or poles of inclination. The two main points of this type are commonly referred to as the magnetic poles of the Earth. One of them is in the Arctic, the second - in Antarctica. On the era 1965 Their coordinates were respectively 75 °, 6 S.Sh., 101 ° C. and 66 °, 3 yu.sh., 141 ° V.D.

At any point P on the spherical surface there is a natural direction characterizing this point - a radial direction. Since H, Z and I are determined relative to this direction, and in general does not require any direction to determine any direction, these four components can be called their own magnetic elements. But in can not be determined by only these elements. To determine the azimuth H, you need to select some zero direction, from which you can count the magnetic declination of D. The direction on the northern geographic pole is chosen as such a direction. Since the axis of rotation of the Earth is not directly related to the configuration of the geomagnetic field, D (like X, Y) is determined relative to the conditional direction adopted on the basis of a simple agreement. Therefore, D, X and Y can be called relative magnetic elements.

Magnetic field tension

vector physical quantity (N.), which is the quantitative characteristic of the magnetic field (see the magnetic field). N. m. N. Does not depend on the magnetic properties of the medium. In Vacuum N. m. P. Coincides with magnetic induction (see Magnetic Induction) AT; numerically N. = AT in the SSS system units (see SGS system units) and N. = AT/μ 0 In the international system of units (see the international system of units) (C), μ 0 is a magnetic constant. In medium N. mp. N. Determines the contribution to magnetic induction ATwhich give external field sources: N. = AT - 4π. j. (in the SGS Unit), or N. = (B /μ 0 ) - j. (in SI), where j. - Magnetization of the medium. If you enter a relative magnetic permeability (see Magnetic permeability) of the medium μ, then for an isotropic medium N. = AT/ μ 0 μ (in SI). Unit of N. m. P. in C is ampere per meter ( a / M.), in the system of units of the SSS - Ersted ( e.); 1 a / M. \u003d 4π.10 -3. e. ≅ 1,256․10 -2 e..

N. m. P. Straight conductor with current I. (in SI) N. = μ 0 I /2π. a. (but - distance from the conductor); in the center of the circular current N. = μ 0 i / 2R (R. - Radius turn with current I.); In the center of the solenoid on its axis N. = μ 0 ni. (n. - the number of turns per unit length of the solenoid). Practical definition N. in ferromagnetic media (in magnetic materials (see magnetic materials)) is based on the fact that the tangential component N. Does not change when moving from one environment to another. With homogeneous body magnetization, the tension measured on its surface parallel to the direction of magnetization corresponds to the tension inside the body. Methods for measuring N. m. P. Considered in Art. Magnetic measurements, magnetometer.

Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

Watch what is "magnetic field tense" in other dictionaries:

Dimension L-1i units of measurement ... Wikipedia

Vector n, which is quantities. Har Koy Magn. Fields. N. m. P. Not dependent on Magn. SV in the medium. In Vacuum N. m. P. Coincides with the magnetic induction of B, numerically H \u003d B in the SSS system of units and H \u003d V / M0 in the international system of units (C), M0 ... ... Physical encyclopedia

- (h), vector characteristic of the magnetic field, independent of the magnetic properties of the medium. In vacuum h coincides (in units) with magnetic induction V. In medium H, it defines the contribution to the magnetic induction that external (with respect to the medium) ... ... Modern encyclopedia

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Magnetic field tension - magnetic field tension The tension of the magnetic field (H), the vector characteristic of the magnetic field, independent of the magnetic properties of the medium. In vacuum h coincides (in units. SGS) with magnetic induction. V. In Wednesday, it defines the contribution to ... ... Illustrated Encyclopedic Dictionary

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magnetic field tension - Magnetinio Lauko Stipris Statusas T Sritis Fizika Atitikmenys: Angl. Magnetic Field Intensity; Magnetic Field Strength Vok. Magnetfeldstärke, f; Magnetische Feldstärke, F Rus. Magnetic field tension, F pranc. INTENSITÉ DE CHAMP MAGNÉTIQUE ... FIZIKOS TERMINų žODYNAS

- (H), power characteristic magnetic field, independent of the magnetic properties of the medium. In vacuo, H coincides (in units of the SGS) with magnetic induction V. In the environment, it defines the contribution to the magnetic induction, which is given external sources of the field. * * * ... ... encyclopedic Dictionary

Vector n, characterizing a magnetic field. N. m. P. equals geom. The difference in magnetic induction in the considered point of the field divided by the magnetic constant N0, and the magnetization of the medium M at this point of the field: H \u003d V / N0 M. If the environment ... ... Big Encyclopedic Polytechnic Dictionary

- (H), vector magnitude, power characteristic of magicians, fields independent of Magn. Properties of the medium. In Vacuum N. m. P. Coincides (in units. SGS) with Magn. Induction V. in the N. m. P. Defines the contribution to Magn. Induction, to ryy give external. Sources of the field ... Natural science. encyclopedic Dictionary

Selected article

Magnetic field tension

General

Magnetic field tension and magnetic induction. It would seem why was the physicists complicate the already complex physical concepts in describing the phenomena of magnetism? Two vectors, equally directed, distinguished except with the ratio of proportionality - well, what's the point of view in this sense simple man, not too burdened knowledge from the field of modern physics?

Nevertheless, it is in this distinction that the nuances are hidden, which allowed scientists to open and amazing properties of various substances, and the laws of their interaction with the magnetic field, and even change our ideas about the environment.

In fact, this difference hides a different methodological approach. Simplifically speaking, in the case of using the concept of the tension of the magnetic field, we neglect the influence of the magnetic field on the substance in a particular case; In the case of applying the concept of magnetic induction, we take into account this factor.

From a technical point of view, the tension of the magnetic field is quite a complex configuration just to calculate, and the resulting magnetic induction is measured.

For this apparent simplicity, the titanic work is hidden by the whole populad of scientists separated in time and space. Their ideas and concepts identified and determine the development of science and technology in the past, present and future.

And it doesn't matter how soon we will master thermonuclear energy using a new generation of thermonuclear reactors based on the holding of the "hot" plasma by a magnetic field. When we send new generations of research robots on missiles based on the use of other principles than burning chemical fuels. Or, in particular, by solving the problem of correction of the orbits of microstects by the engines of the hall. Or how fully will be able to utilize the energy of the Sun, as quickly and cheaply we can move around our planet - the names of the pioneers of science forever will remain in our memory.

The current generation of scientists and engineers of the twenty-first century, armed with the accumulated knowledge of their predecessors, will be submitted by the task of magnetic levitation, until tested in laboratories and pilot projects; and the problem of extracting energy from ambient With the help of the technical implementation of the "Demon Maxwell" using unprecedented materials and the interactions of a new type. The first prototypes of such devices have already appeared on KiSkstarter.

At the same time, the main problem of humanity will be solved - transformation into heat accumulated over the hundreds of millions of years of reserves of coal and hydrocarbons, mercilessly changing the combustion products of our planet. And the coming thermonuclear revolution, guaranteed, following its thoughtless learning, the thermal death of any organic life on Earth will not become a death sentence of civilization. After all, the energy of any kind that we spend, in the end turns into heat and heats our planet.

Case for small - time; Live - see!

Historical reference

Despite the fact that the magnets and phenomenon of magnetization were known from the long time, the scientific study of magnetism began with the works of the French medieval scientist Pierre Pierena de Marikura in a distant 1269. De Marikur signed his works by the name of Petrus Orelin (Lat. Petrus Peregrinus).

Exploring the behavior of an iron needle near a spherical magnet, the scientist found that the needle actively behaves near two points, called them poles. So it is waved to give an analogy with the magnetic poles of the Earth, but at that time, for such an image of thoughts, it was easy to go to the fire! In addition, the researcher found that any magnet always has (in modern presentation) North and South Poles. And how do not open the magnet in the longitudinal or in cross section, all the same, each of the produced magnets will always have two poles, no matter how thin it was.

The "Kramolny" idea that the Earth itself is a magnet, was published by the English doctor and naturalist William Gilbert in the work of "De Magne", which saw the light of almost three centuries later in 1600.

In 1750, English scientist John Mitchell found that magnets are attracted and repel (interact) in accordance with the law of "back squares". In 1785, the French scientist Charles Morestin de Peon experimentally checked the assumptions of Mitchell and found that the northern and southern magnetic poles cannot be disconnected. However, by analogy with their previously open interaction electrical charges, The pendant has yet suggested existence and magnetic charges - hypothetical magnetic monopoles.

Based on the facts of magnetism known to him at that time in science in science, a methodological approach to the construction of interaction theories as some liquids, in 1824, Culon Simeon's compatriot Denis Poisson created the first successful model of magnetism. In his theoretical model, the magnetic field was described by dipoles of magnetic charges.

But literally immediately three discoveries in a row questioned the Poisson model. Consider them below.

Danish physicist Hans Christian Ersted in 1819 noticed the deviation of the magnetic compass arrows when turned on and disabled electric currentflowing through the conductor in the form of a wire, thus finding the relationship between electricity and magnetism.

In 1820, the French scientist Andre-Marie Ampere found that conductors with currents flowing in one direction are attracted, and in the opposite - repel. In the same 1820, French physics Jean-Batist Bio and Felix Savar discovered the law called by their names. This law allowed to calculate the voltage of the magnetic field around any conductor with a current, regardless of its geometric configuration.

Summarizing the resulting theoretical and experimental data, Ampere expressed the idea of \u200b\u200bthe equivalence of electrical currents and manifestations of magnetism. He developed his model of magnetism, in which he replaced magnetic dipoles with circulation of electrical currents in tiny closed loops. The model of manifestation of Magnetism Ampere had an advantage over the Poisson model, since explained the impossibility of separating the poles of magnets.

Ampere also proposed for describing such phenomena the term "electrodynamics", which expanded the use of science on electricity to dynamic electrical objects, thereby complementing the electrostatics. Perhaps the greatest impact on the understanding of the essence of the manifestations of magnetism was provided by the concept of representing the interaction of magnets through the power field described by the power lines proposed by the English scientist Michael Faraday. Opened in 1831 by Faraday phenomenon electromagnetic induction Later was explained by the German mathematician Franz Ernst Neumanan. The latter proved that the occurrence of electric current in a closed circuit with a change in the magnetic flux passing through it is simply a consequence of the AMPER's law. Neumani introduced the concept of vector magnetic potential into the science of science, which is largely equivalent to the voltage lines of the magnetic field of Faraday.

The final point in the dispute of two models of magnetism put in 1850 an outstanding English physicist William Thompson (Lord Kelvin). Entering the concept of magnetization of the medium M.in which there is a magnetic field, it not only established the dependence between the voltage of the magnetic field H. and magnetic induction vector B.But also determined the areas of applicability of these concepts.

The tension of the magnetic field. Definition

The tension of the magnetic field is a vector physical value equal to the difference in magnetic induction vector B. and vector magnetization M.. In the international system of units (s), the magnetic field voltage value is determined by the formula:

H. \u003d (1 / μ 0) ∙ B. - M.

where μ0 is a magnetic constant, sometimes it is called the magnetic permeability of a vacuum

In the system of units of the GSS, the magnetic field strength is determined by another formula:

N. = B. - 4 ∙ π ∙ M.

In the international system of SI units, the voltage of the magnetic field is measured in amperes per meter (A / m), in the SSS system - in Erusted (E).

In electrical engineering, there is also an introductory unit of measurement of tension - ampere-turn to the meter. With other magnitudes of measuring the voltage of the magnetic field used in various applications, and their translations from one value to another can be found in the converter of physical quantities.

Measuring instruments for measuring the magnetic field tension values, as well as instruments for measuring magnetic induction, are called tall meters or magnetometers.

The tension of the magnetic field. Physics phenomena

Research Tokamak ( thatroidal kameasure S. ma.night coils), who worked in the Research Institute of the State Energy Company Hydro-Québec in the suburb of Montreal, from 1987 to 1997, when the project was closed to economy budget funds. Installation is located in the exposition of the Canadian Museum of Science and Technology

In vacuo (in the classical understanding of this term) or in the absence of a medium capable of magnetic polarization or in cases where the magnetic polarization of the medium can be neglected, the tension of the magnetic field N. Coincides (with accuracy to the coefficient) with a magnetic induction vector AT. For the SGS system, this coefficient is 1, for the system SI-μ0 system.

The tension of the magnetic field is due to free (external) currents that easily measure or calculate. That is, the tension makes sense for an external magnetic field created by a coil with a current into which the material is inserted capable of magnifying. If we are not interested in the behavior of the material under the action of a magnetic field, then it is enough to operate only by the tension of the magnetic field. For example, tensions will be enough for the technical calculation of the interaction of magnetic fields of two or more coils with a current. The resulting tension will be a vector amount of fields created by separate coils with a current.

Since most electromagnetic devices are operating in the air, it is important to know its magnetic permeability. The absolute magnetic permeability of the air is approximately equal to the magnetic permeability of the vacuum and in the technical calculations is made equal to 4π 10 ° C / m.

This is the case when we are interested in the behavior of an environment capable of magnetization, for example, when using nuclear magnetorezonance phenomena. In NMR, the nucleus of atoms, otherwise called nucleons and having a half-spin (magnetic moment), when exposed to a magnetic field absorbed or emit electromagnetic energy at certain frequencies. In these cases, it is necessary to consider the magnetic induction.

Application of the tension of the magnetic field in the technique

In most cases, the practical application of the magnetic field, for example, to create it or to measure its magnitude, the voltage of the magnetic field plays a key role. There are many examples of using the magnetic field, primarily in the measuring equipment and in various installations For experiments.

The magnetic field of a certain force and configuration holds plasma cords or streams of charged particles in research thermonuclear reactors and in elementary particle accelerators, thereby preventing the plasma cooling during contact with the enclosing walls. It deflects the flows of ions or electrons in spectrometers and kinescopes.

Measuring the tension of the magnetic field of the Earth at different points is very important to estimate its magnetosphere. There is even a whole network of ground stations and groups of scientific satellites to monitor the voltage of the magnetic field of the Earth. Their work allows you to predict magnetic storms arising in the sun, minimizing as much as possible, their consequences.

Measuring the field strength makes it possible to carry out various research, sort materials and garbage, as well as provide our safety, detecting terrorist weapons or mortgaged mines.

Magnetometers

The magnetometers are called a whole class of measuring instruments designed to measure the magnetization of materials or to determine the strength and direction of the magnetic field.

The first magnetometer was invented by a great German mathematician and physicist Carl Friedrich Gauss in 1833. This device was an optical instrument with a rotating magnetized rod suspended on a golden thread, and perpendicular to the axis of the magnet mirror is perpendicular to it. The difference in the oscillations of the magnetized and demagnetic rod was measured.

Now they use more sensitive magnetometers on other principles, in particular, on the Hall sensors, Josephson tunnel contacts (squid magnetometers) induction and NMR resonance. They are widely used in various applications: measuring the magnetic field of the Earth, in geophysical studies of magnetic anomalies and in finding minerals; In a military case for detecting objects such as submarines, sunken ships or disguised tanks, distorting the Magnetic field of the earth; To search for unexploded or mortgaged ammunition at the fighting places. Due to miniaturization and reduction of current consumption, smartphones and tablets are equipped with modern magnetometers. Nowadays, magnetometers are included as an integral component into equipment of reconnaissance unmanned aerial vehicles and spy satellites.

Curious item: Due to the increase in the sensitivity of magnetometers, one of the factors of the construction of submarines on titanium corps instead of steel housings was precisely a radical decline in their visibility in a magnetic field. Previously, submarines with a steel case, as, however, and surface ships, had to undergo a demagnetization procedure from time to time.

The magnetometers are used when drilling wells and penetration of gallery, in archeology to protrude excavation and search for artifacts, in biology and medicine.

Metal detectors

Attempts to use the tension of the magnetic field in military affairs have been made since the First World War, which left millions of unexploded ammunition on the battlefields and installed mines. The most successful was to develop in the early 40s of the last century, the lieutenant of the Polish army of Jozef Stanislav Kozatsky, adopted by the British army and served a lot of benefit when neutralizing minefields during the pursuit of the Germans of General Montgomery with the second battle under El Alamery. Despite the fact that the equipment of Cochatsky was performed on electronic lamps, it weighed only 14 kilograms together with batteries and was so effective that its modifications were used by the British army for 50 years.

Now it is not surprising, due to the spread of terrorism, passing before landing on the aircraft or on football matches through the induction framework of metal detectors, examination of the protection of objects of our baggage or personal loaning of manual metal detectors to detect weapons.

Widely distribution and household metal detectors received, on the beaches of fashionable resorts, became the usual picture of seekers of lost treasures, reading local beaches in the hope of finding anything valuable.

Correlation analysis of solar and geomagnetic activity

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Watch what is "magnetic field tense" in other dictionaries:

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