A magnetic field- this is a material medium through which the interaction between conductors with current or moving charges is carried out.

Properties magnetic field :

Magnetic field characteristics:

To study the magnetic field, a test circuit with current is used. It is small, and the current in it is much less than the current in the conductor that creates the magnetic field. On opposite sides of the circuit with current from the side of the magnetic field, forces act that are equal in magnitude, but directed in opposite directions, since the direction of the force depends on the direction of the current. The points of application of these forces do not lie on one straight line. Such forces are called a couple of forces. As a result of the action of a pair of forces, the contour cannot move forward, it rotates around its axis. The rotating action is characterized torque.

, Where l–arm of a pair of forces(distance between points of application of forces).

With an increase in current in a test circuit or circuit area, the moment of a pair of forces will increase proportionally. The ratio of the maximum moment of forces acting on the current-carrying circuit to the magnitude of the current in the circuit and the area of ​​the circuit is a constant value for a given point of the field. It's called magnetic induction.

, Where
-magnetic moment circuits with current.

Unit magnetic induction - Tesla [T].

Magnetic moment of the circuit- vector quantity, the direction of which depends on the direction of the current in the circuit and is determined by right screw rule: clench your right hand into a fist, point four fingers in the direction of the current in the circuit, then the thumb will indicate the direction of the magnetic moment vector. The magnetic moment vector is always perpendicular to the contour plane.

Behind direction of magnetic induction vector take the direction of the vector of the magnetic moment of the circuit oriented in the magnetic field.

Line of magnetic induction- a line, the tangent to which at each point coincides with the direction of the magnetic induction vector. The lines of magnetic induction are always closed, never intersect. Lines of magnetic induction of a straight conductor with current have the form of circles located in a plane perpendicular to the conductor. The direction of the lines of magnetic induction is determined by the rule of the right screw. Lines of magnetic induction of circular current(coil with current) also have the form of circles. Each coil element is long
can be thought of as a straight conductor that creates its own magnetic field. For magnetic fields, the principle of superposition (independent addition) is fulfilled. The total vector of the magnetic induction of the circular current is determined as the result of the addition of these fields in the center of the coil according to the rule of the right screw.

If the magnitude and direction of the magnetic induction vector are the same at each point in space, then the magnetic field is called homogeneous. If the magnitude and direction of the magnetic induction vector at each point do not change over time, then such a field is called permanent.

Value magnetic induction at any point of the field is directly proportional to the current strength in the conductor that creates the field, is inversely proportional to the distance from the conductor to a given point in the field, depends on the properties of the medium and the shape of the conductor that creates the field.

, Where
ON 2 ; H/m is the vacuum magnetic constant,

-relative magnetic permeability of the medium,

-absolute magnetic permeability of the medium.

Depending on the magnitude of the magnetic permeability, all substances are divided into three classes:

With an increase in the absolute permeability of the medium, the magnetic induction at a given point of the field also increases. The ratio of magnetic induction to the absolute magnetic permeability of the medium is a constant value for a given point of the poly, e is called tension.

.

The vectors of tension and magnetic induction coincide in direction. The strength of the magnetic field does not depend on the properties of the medium.

Amp power- the force with which the magnetic field acts on a conductor with current.

Where l- the length of the conductor, - the angle between the vector of magnetic induction and the direction of the current.

The direction of the Ampere force is determined by left hand rule: the left hand is positioned so that the component of the magnetic induction vector, perpendicular to the conductor, enters the palm, direct four outstretched fingers along the current, then the thumb bent by 90 0 will indicate the direction of the Ampere force.

The result of the action of the Ampere force is the movement of the conductor in a given direction.

E if = 90 0 , then F=max, if = 0 0 , then F= 0.

Lorentz force- the force of the magnetic field on the moving charge.

, where q is the charge, v is the speed of its movement, - the angle between the vectors of tension and velocity.

The Lorentz force is always perpendicular to the magnetic induction and velocity vectors. The direction is determined by left hand rule(fingers - on the movement of a positive charge). If the direction of particle velocity is perpendicular to the lines of magnetic induction of a uniform magnetic field, then the particle moves in a circle without changing the kinetic energy.

Since the direction of the Lorentz force depends on the sign of the charge, it is used to separate charges.

magnetic flux - a value equal to the number of lines of magnetic induction that pass through any area located perpendicular to the lines of magnetic induction.

, Where - the angle between the magnetic induction and the normal (perpendicular) to the area S.

Unit– Weber [Wb].

Methods for measuring magnetic flux:

Changing the orientation of the site in a magnetic field (changing the angle)

Change in the area of ​​a contour placed in a magnetic field

Changing the strength of the current that creates the magnetic field

Changing the distance of the contour from the source of the magnetic field

Change in the magnetic properties of the medium.

F Aradey registered electricity in a path that does not contain a source but is adjacent to another path containing a source. Moreover, the current in the primary circuit arose in the following cases: with any change in the current in circuit A, with relative movement of the circuits, with the introduction of an iron rod into circuit A, with movement of a permanent magnet relative to circuit B. The directed movement of free charges (current) occurs only in an electric field. This means that a changing magnetic field generates an electric field, which sets the free charges of the conductor in motion. This electric field is called induced or eddy.

Differences between a vortex electric field and an electrostatic one:

The source of the vortex field is a changing magnetic field.

The lines of the vortex field strength are closed.

The work done by this field to move the charge along a closed circuit is not equal to zero.

The energy characteristic of the vortex field is not the potential, but EMF induction - a value equal to the work of external forces (forces of non-electrostatic origin) in moving a unit of charge along a closed circuit.

.Measured in Volts[IN].

A vortex electric field arises with any change in the magnetic field, regardless of whether there is a conducting closed loop or not. The contour only allows to detect the vortex electric field.

Electromagnetic induction- this is the occurrence of an EMF of induction in a closed circuit with any change in the magnetic flux through its surface.

EMF of induction in a closed circuit generates an inductive current.

.

Direction of induction current determined by Lenz's rule: the induction current has such a direction that the magnetic field created by it opposes any change in the magnetic flux that generated this current.

Faraday's law for electromagnetic induction: EMF of induction in a closed loop is directly proportional to the rate of change of the magnetic flux through the surface bounded by the loop.

T okie foucault- eddy induction currents that occur in large conductors placed in a changing magnetic field. The resistance of such a conductor is small, since it has a large cross section S, so the Foucault currents can be large in magnitude, as a result of which the conductor heats up.

self induction- this is the occurrence of an EMF of induction in a conductor when the current strength in it changes.

A current-carrying conductor creates a magnetic field. Magnetic induction depends on the strength of the current, therefore, the own magnetic flux also depends on the strength of the current.

, where L is the coefficient of proportionality, inductance.

Unit inductance - Henry [H].

Inductance conductor depends on its size, shape and magnetic permeability of the medium.

Inductance increases with the length of the conductor, the inductance of the coil is greater than the inductance of a straight conductor of the same length, the inductance of the coil (a conductor with a large number of turns) is greater than the inductance of one turn, the inductance of the coil increases if an iron rod is inserted into it.

Faraday's law for self-induction:
.

EMF self-induction directly proportional to the rate of change of current.

EMF self-induction generates a self-induction current, which always prevents any change in the current in the circuit, that is, if the current increases, the self-induction current is directed in the opposite direction, when the current in the circuit decreases, the self-induction current is directed in the same direction. The greater the inductance of the coil, the more self-inductance EMF occurs in it.

Magnetic field energy is equal to the work that the current does to overcome the self-induction EMF during the time until the current increases from zero to a maximum value.

.

Electromagnetic vibrations- these are periodic changes in charge, current strength and all characteristics of electric and magnetic fields.

Electric oscillatory system(oscillatory circuit) consists of a capacitor and an inductor.

Conditions for the occurrence of vibrations:

The system must be brought out of equilibrium; for this, a charge is imparted to the capacitor. The energy of the electric field of a charged capacitor:

.

The system must return to a state of equilibrium. Under the influence of an electric field, the charge passes from one plate of the capacitor to another, that is, an electric current arises in the circuit, which flows through the coil. With an increase in current in the inductor, an EMF of self-induction arises, the self-induction current is directed in the opposite direction. When the current in the coil decreases, the self-induction current is directed in the same direction. Thus, the self-induction current tends to return the system to a state of equilibrium.

The electrical resistance of the circuit must be small.

Ideal oscillatory circuit has no resistance. The oscillations in it are called free.

For any electrical circuit, Ohm's law is fulfilled, according to which the EMF acting in the circuit is equal to the sum of the voltages in all sections of the circuit. There is no current source in the oscillatory circuit, but self-induction EMF arises in the inductor, which is equal to the voltage across the capacitor.

Conclusion: the charge of the capacitor changes according to the harmonic law.

Capacitor voltage:
.

Loop current:
.

Value
- the amplitude of the current strength.

The difference from the charge on
.

The period of free oscillations in the circuit:

Capacitor electric field energy:

Coil magnetic field energy:

The energies of the electric and magnetic fields change according to a harmonic law, but the phases of their oscillations are different: when the energy of the electric field is maximum, the energy of the magnetic field is zero.

Total energy of the oscillatory system:
.

IN ideal contour the total energy does not change.

In the process of oscillations, the energy of the electric field is completely converted into the energy of the magnetic field and vice versa. So the energy at any moment of time is equal to or maximum energy electric field, or the maximum energy of the magnetic field.

Real oscillatory circuit contains resistance. The oscillations in it are called fading.

Ohm's law takes the form:

Provided that the damping is small (the square of the natural oscillation frequency is much greater than the square of the damping coefficient), the logarithmic damping decrement:

With strong damping (the square of the natural oscillation frequency is less than the square of the oscillation coefficient):

This equation describes the process of discharging a capacitor across a resistor. In the absence of inductance, oscillations will not occur. According to this law, the voltage across the capacitor plates also changes.

total energy in a real circuit, it decreases, since heat is released on the resistance R when current passes.

transition process- a process that occurs in electrical circuits during the transition from one mode of operation to another. Estimated time ( ), during which the parameter characterizing the transient process will change in e times.

For circuit with capacitor and resistor:
.

Maxwell's theory of the electromagnetic field:

1 position:

Any alternating electric field generates a vortex magnetic field. An alternating electric field was called by Maxwell a displacement current, since it, like an ordinary current, induces a magnetic field.

To detect the displacement current, the passage of current through the system, which includes a capacitor with a dielectric, is considered.

Bias current density:
. The current density is directed in the direction of the change in intensity.

Maxwell's first equation:
- the vortex magnetic field is generated both by conduction currents (moving electric charges) and displacement currents (alternating electric field E).

2 position:

Any alternating magnetic field generates a vortex electric field - the basic law of electromagnetic induction.

Maxwell's second equation:
- relates the rate of change of the magnetic flux through any surface and the circulation of the vector of the electric field strength that arises in this case.

Any conductor with current creates a magnetic field in space. If the current is constant (does not change over time), then the associated magnetic field is also constant. The changing current creates a changing magnetic field. There is an electric field inside a current-carrying conductor. Therefore, a changing electric field creates a changing magnetic field.

The magnetic field is vortex, since the lines of magnetic induction are always closed. The magnitude of the magnetic field strength H is proportional to the rate of change of the electric field strength . Direction of the magnetic field vector associated with a change in the electric field strength by the rule of the right screw: clench the right hand into a fist, point the thumb in the direction of the change in the electric field strength, then the bent 4 fingers will indicate the direction of the lines of the magnetic field strength.

Any changing magnetic field creates a vortex electric field, whose strength lines are closed and located in a plane perpendicular to the magnetic field strength.

The magnitude of the intensity E of the vortex electric field depends on the rate of change of the magnetic field . The direction of the vector E is related to the direction of the change in the magnetic field H by the rule of the left screw: clench the left hand into a fist, point the thumb in the direction of the change in the magnetic field, bent four fingers will indicate the direction of the lines of the vortex electric field.

The set of vortex electric and magnetic fields connected with each other represent electromagnetic field. The electromagnetic field does not remain in the place of origin, but propagates in space in the form of a transverse electromagnetic wave.

electromagnetic wave- this is the distribution in space of vortex electric and magnetic fields connected with each other.

The condition for the occurrence of an electromagnetic wave- movement of the charge with acceleration.

Electromagnetic wave equation:

- cyclic frequency of electromagnetic oscillations

t is the time from the start of oscillations

l is the distance from the wave source to a given point in space

- wave propagation speed

The time it takes a wave to travel from a source to a given point.

The vectors E and H in an electromagnetic wave are perpendicular to each other and to the speed of wave propagation.

Source of electromagnetic waves- conductors through which fast-alternating currents (macro-emitters), as well as excited atoms and molecules (micro-emitters) flow. The higher the oscillation frequency, the better the electromagnetic waves are emitted in space.

Properties of electromagnetic waves:

All electromagnetic waves transverse

In a homogeneous medium, electromagnetic waves propagate at a constant speed, which depends on the properties of the environment:

- relative permittivity of the medium

is the vacuum dielectric constant,
F/m, Cl 2 /nm 2

- relative magnetic permeability of the medium

- vacuum magnetic constant,
ON 2 ; H/m

Electromagnetic waves reflected from obstacles, absorbed, scattered, refracted, polarized, diffracted, interfered.

Volumetric energy density electromagnetic field consists of volumetric energy densities of electric and magnetic fields:

Wave energy flux density - wave intensity:

-Umov-Poynting vector.

All electromagnetic waves are arranged in a series of frequencies or wavelengths (
). This row is electromagnetic wave scale.

Low frequency vibrations. 0 - 10 4 Hz. Obtained from generators. They don't radiate well.

radio waves. 10 4 - 10 13 Hz. Radiated by solid conductors, through which fast-alternating currents pass.

Infrared radiation- waves emitted by all bodies at temperatures above 0 K, due to intra-atomic and intra-molecular processes.

visible light- waves that act on the eye, causing a visual sensation. 380-760 nm

Ultraviolet radiation. 10 - 380 nm. Visible light and UV arise when the motion of electrons in the outer shells of an atom changes.

x-ray radiation. 80 - 10 -5 nm. Occurs when the motion of electrons in the inner shells of an atom changes.

Gamma radiation. Occurs during the decay of atomic nuclei.

On the Internet there are a lot of topics devoted to the study of the magnetic field. It should be noted that many of them differ from the average description that exists in school textbooks. My task is to collect and systematize all the freely available material on the magnetic field in order to focus the New Understanding of the magnetic field. The study of the magnetic field and its properties can be done using a variety of techniques. With the help of iron filings, for example, a competent analysis was carried out by Comrade Fatyanov at http://fatyf.narod.ru/Addition-list.htm

With the help of a kinescope. I do not know the name of this person, but I know his nickname. He calls himself "The Wind". When a magnet is brought to the kinescope, a "honeycomb picture" is formed on the screen. You might think that the "grid" is a continuation of the kinescope grid. This is a method of visualizing the magnetic field.

I began to study the magnetic field with the help of a ferrofluid. It is the magnetic fluid that maximally visualizes all the subtleties of the magnetic field of the magnet.

From the article "what is a magnet" we found out that a magnet is fractalized, i.e. a scaled-down copy of our planet, the magnetic geometry of which is as identical as possible to a simple magnet. The planet earth, in turn, is a copy of what it was formed from - the sun. We found out that a magnet is a kind of inductive lens that focuses on its volume all the properties of the global magnet of the planet earth. There is a need to introduce new terms with which we will describe the properties of the magnetic field.

The induction flow is the flow that originates at the poles of the planet and passes through us in a funnel geometry. The planet's north pole is the entrance to the funnel, the planet's south pole is the exit of the funnel. Some scientists call this stream the ethereal wind, saying that it is "of galactic origin." But this is not an "ethereal wind" and no matter what the ether is, it is an "induction river" that flows from pole to pole. The electricity in lightning is of the same nature as the electricity produced by the interaction of a coil and a magnet.

The best way to understand what a magnetic field is - to see him. It is possible to think and make countless theories, but from the standpoint of understanding the physical essence of the phenomenon, it is useless. I think that everyone will agree with me, if I repeat the words, I don’t remember who, but the essence is that the best criterion is experience. Experience and more experience.

At home, I did simple experiments, but they allowed me to understand a lot. A simple cylindrical magnet ... And he twisted it this way and that. Poured magnetic fluid on it. It costs an infection, does not move. Then I remembered that on some forum I read that two magnets squeezed by the same poles in a sealed area increase the temperature of the area, and vice versa lower it with opposite poles. If temperature is a consequence of the interaction of fields, then why shouldn't it be the cause? I heated the magnet using a "short circuit" of 12 volts and a resistor by simply leaning the heated resistor against the magnet. The magnet heated up and the magnetic fluid began to twitch at first, and then completely became mobile. The magnetic field is excited by temperature. But how is it, I asked myself, because in the primers they write that temperature weakens the magnetic properties of a magnet. And this is true, but this "weakening" of the kagba is compensated by the excitation of the magnetic field of this magnet. In other words, the magnetic force does not disappear, but is transformed into the force of excitation of this field. Excellent Everything rotates and everything spins. But why does a rotating magnetic field have just such a geometry of rotation, and not some other one? At first glance, the movement is chaotic, but if you look through a microscope, you can see that in this movement system is present. The system does not belong to the magnet in any way, but only localizes it. In other words, a magnet can be considered as an energy lens that focuses perturbations in its volume.

The magnetic field is excited not only by an increase in temperature, but also by its decrease. I think that it would be more correct to say that the magnetic field is excited by a temperature gradient than by one of its specific signs. The fact of the matter is that there is no visible "restructuring" of the structure of the magnetic field. There is a visualization of a disturbance that passes through the region of this magnetic field. Imagine a perturbation that moves in a spiral from the north pole to the south through the entire volume of the planet. So the magnetic field of the magnet = the local part of this global flow. Do you understand? However, I'm not sure which particular thread...But the fact is that the thread. And there are not one stream, but two. The first is external, and the second is inside it and together with the first moves, but rotates in the opposite direction. The magnetic field is excited due to the temperature gradient. But we again distort the essence when we say "the magnetic field is excited." The fact is that it is already in an excited state. When we apply a temperature gradient, we distort this excitation into a state of unbalance. Those. we understand that the process of excitation is a constant process in which the magnetic field of the magnet is located. The gradient distorts the parameters of this process in such a way that we optically notice the difference between its normal excitation and the excitation caused by the gradient.

But why is the magnetic field of a magnet stationary in a stationary state? NO, it is also mobile, but relative to moving frames of reference, for example us, it is motionless. We move in space with this perturbation of Ra and it seems to us to be moving. The temperature we apply to the magnet creates some kind of local imbalance in this focusable system. A certain instability appears in the spatial lattice, which is the honeycomb structure. After all, bees do not build their houses from scratch, but they stick around the structure of space with their building material. Thus, based on purely experimental observations, I conclude that the magnetic field simple magnet this is a potential system of local unbalance of the lattice of space, in which, as you may have guessed, there is no place for atoms and molecules that no one has ever seen. Temperature, like an "ignition key" in this local system, turns on the imbalance. At the moment, I am carefully studying the methods and means of managing this imbalance.

What is a magnetic field and how is it different from an electromagnetic field?

What is a torsion or energy-informational field?

It's all one and the same, but localized by different methods.

Current strength - there is a plus and a repulsive force,

tension is a minus and a force of attraction,

a short circuit, or let's say a local imbalance of the lattice - there is a resistance to this interpenetration. Or the interpenetration of father, son and holy spirit. Let's remember that the metaphor "Adam and Eve" is an old understanding of X and YG chromosomes. For the understanding of the new is a new understanding of the old. "Strength" - a whirlwind emanating from the constantly rotating Ra, leaving behind an informational weave of itself. Tension is another vortex, but inside the main vortex of Ra and moving along with it. Visually, this can be represented as a shell, the growth of which occurs in the direction of two spirals. The first is external, the second is internal. Or one inside itself and clockwise, and the second out of itself and counterclockwise. When two vortices interpenetrate each other, they form a structure, like the layers of Jupiter, which move in different directions. It remains to understand the mechanism of this interpenetration and the system that is formed.

Approximate tasks for 2015

1. Find methods and means of unbalancing control.

2. Identify the materials that most affect the imbalance of the system. Find the dependence on the state of the material according to table 11 of the child.

3. If anything Living being, in its essence, is the same localized imbalance, therefore it must be "seen". In other words, it is necessary to find a method for fixing a person in other frequency spectra.

4. The main task is to visualize non-biological frequency spectra in which the continuous process of human creation takes place. For example, with the help of the progress tool, we analyze the frequency spectra that are not included in the biological spectrum of human feelings. But we only register them, but we cannot "realize" them. Therefore, we do not see further than our senses can comprehend. Here is my main goal for 2015. Find a technique for technical awareness of a non-biological frequency spectrum in order to see the information basis of a person. Those. in fact, his soul.

A special kind of study is the magnetic field in motion. If we pour ferrofluid on a magnet, it will occupy the volume of the magnetic field and will be stationary. However, you need to check the experience of "Veterok" where he brought the magnet to the monitor screen. There is an assumption that the magnetic field is already in an excited state, but the volume of liquid kagba restrains it in a stationary state. But I haven't checked yet.

The magnetic field can be generated by applying temperature to the magnet, or by placing the magnet in an induction coil. It should be noted that the liquid is excited only at a certain spatial position of the magnet inside the coil, making up a certain angle to the coil axis, which can be found empirically.

I have done dozens of experiments with moving ferrofluid and set myself goals:

1. Reveal the geometry of fluid motion.

2. Identify the parameters that affect the geometry of this movement.

3. What is the place of fluid movement in the global movement of the planet Earth.

4. Whether the spatial position of the magnet and the geometry of movement acquired by it depend.

5. Why "ribbons"?

6. Why Ribbons Curl

7. What determines the vector of twisting of the tapes

8. Why the cones are displaced only by means of nodes, which are the vertices of the honeycomb, and only three adjacent ribbons are always twisted.

9. Why does the displacement of the cones occur abruptly, upon reaching a certain "twist" in the nodes?

10. Why the size of the cones is proportional to the volume and mass of the liquid poured onto the magnet

11. Why the cone is divided into two distinct sectors.

12. What is the place of this "separation" in terms of interaction between the poles of the planet.

13. How does the geometry of fluid movement depend on the time of day, season, solar activity, intention of the experimenter, pressure and additional gradients. For example, a sharp change "cold hot"

14. Why the geometry of cones identical with Varji geometry- the special weapons of the returning gods?

15. Are there any data in the archives of special services of 5 automatic weapons about the purpose, availability or storage of samples of this type of weapon.

16. What do the gutted pantries of knowledge of various secret organizations say about these cones and whether the geometry of the cones is connected with the Star of David, the essence of which is the identity of the geometry of the cones. (Masons, Jews, Vaticans, and other inconsistent formations).

17. Why there is always a leader among the cones. Those. a cone with a "crown" on top, which "organizes" the movements of 5,6,7 cones around itself.

cone at the moment of displacement. Jerk. "... only by moving the letter "G" I will reach him "...

Just as an electric charge at rest acts on another charge through an electric field, an electric current acts on another current through magnetic field. The action of a magnetic field on permanent magnets is reduced to its action on charges moving in the atoms of a substance and creating microscopic circular currents.

Doctrine of electromagnetism based on two assumptions:

• the magnetic field acts on moving charges and currents;
• a magnetic field arises around currents and moving charges.

Interaction of magnets

Permanent magnet(or magnetic needle) is oriented along the magnetic meridian of the Earth. The end pointing north is called north pole(N) and the opposite end is south pole(S). Approaching two magnets to each other, we note that their poles of the same name repel, and their opposite poles attract ( rice. 1 ).

If we separate the poles by cutting the permanent magnet into two parts, then we will find that each of them will also have two poles, i.e. will permanent magnet (rice. 2 ). Both poles - north and south - are inseparable from each other, equal.

The magnetic field created by the Earth or permanent magnets is depicted, like the electric field, by magnetic lines of force. A picture of the magnetic field lines of any magnet can be obtained by placing a sheet of paper over it, on which iron filings are poured in a uniform layer. Getting into a magnetic field, the sawdust is magnetized - each of them has a north and south poles. Opposite poles tend to approach each other, but this is prevented by the friction of sawdust on paper. If you tap the paper with your finger, the friction will decrease and the filings will be attracted to each other, forming chains that represent the lines of a magnetic field.

On rice. 3 shows the location in the field of a direct magnet of sawdust and small magnetic arrows indicating the direction of the magnetic field lines. For this direction, the direction of the north pole of the magnetic needle is taken.

Oersted's experience. Magnetic field current

IN early XIX V. Danish scientist Oersted did important discovery, discovering action of electric current on permanent magnets . He placed a long wire near the magnetic needle. When a current was passed through the wire, the arrow turned, trying to be perpendicular to it ( rice. 4 ). This could be explained by the appearance of a magnetic field around the conductor.

The magnetic lines of force of the field created by a direct conductor with current are concentric circles located in a plane perpendicular to it, with centers at the point through which the current passes ( rice. 5 ). The direction of the lines is determined by the right screw rule:

If the screw is rotated in the direction of the field lines, it will move in the direction of the current in the conductor .

The force characteristic of the magnetic field is magnetic induction vector B . At each point, it is directed tangentially to the field line. Electric field lines start on positive charges and end on negative ones, and the force acting in this field on a charge is directed tangentially to the line at each of its points. Unlike the electric field, the lines of the magnetic field are closed, which is due to the absence of "magnetic charges" in nature.

The magnetic field of the current is fundamentally no different from the field created by a permanent magnet. In this sense, an analogue of a flat magnet is a long solenoid - a coil of wire, the length of which is much greater than its diameter. The diagram of the lines of the magnetic field he created, depicted in rice. 6 , similar to that for a flat magnet ( rice. 3 ). The circles indicate the sections of the wire forming the solenoid winding. The currents flowing through the wire from the observer are indicated by crosses, and the currents in the opposite direction - towards the observer - are indicated by dots. The same designations are accepted for magnetic field lines when they are perpendicular to the plane of the drawing ( rice. 7 a, b).

The direction of the current in the solenoid winding and the direction of the magnetic field lines inside it are also related by the right screw rule, which in this case is formulated as follows:

If you look along the axis of the solenoid, then the current flowing in the clockwise direction creates a magnetic field in it, the direction of which coincides with the direction of movement of the right screw ( rice. 8 )

Based on this rule, it is easy to figure out that the solenoid shown in rice. 6 , its right end is the north pole, and its left end is the south pole.

The magnetic field inside the solenoid is homogeneous - the magnetic induction vector has a constant value there (B = const). In this respect, the solenoid is similar to a flat capacitor, inside which a uniform electric field is created.

The force acting in a magnetic field on a conductor with current

It was experimentally established that a force acts on a current-carrying conductor in a magnetic field. In a uniform field, a rectilinear conductor of length l, through which current I flows, located perpendicular to the field vector B, experiences the force: F = I l B .

The direction of the force is determined left hand rule:

If the four outstretched fingers of the left hand are placed in the direction of the current in the conductor, and the palm is perpendicular to the vector B, then the retracted thumb will indicate the direction of the force acting on the conductor (rice. 9 ).

It should be noted that the force acting on a conductor with current in a magnetic field is not directed tangentially to its lines of force, like an electric force, but perpendicular to them. A conductor located along the lines of force is not affected by the magnetic force.

The equation F = IlB allows to give a quantitative characteristic of the magnetic field induction.

Attitude does not depend on the properties of the conductor and characterizes the magnetic field itself.

Modulus of magnetic induction vector B numerically equal to strength acting on a conductor of unit length located perpendicular to it, through which a current of one ampere flows.

In the SI system, the unit of magnetic field induction is tesla (T):

A magnetic field. Tables, diagrams, formulas

(Interaction of magnets, Oersted's experiment, magnetic induction vector, vector direction, superposition principle. Graphic representation of magnetic fields, magnetic induction lines. Magnetic flux, field energy characteristic. Magnetic forces, Ampère force, Lorentz force. Movement of charged particles in a magnetic field. Magnetic properties substances, Ampère's hypothesis)

well known wide application magnetic field at home, at work and in scientific research. Suffice it to name such devices as generators alternating current, electric motors, relays, particle accelerators and various sensors. Let us consider in more detail what a magnetic field is and how it is formed.

What is a magnetic field - definition

A magnetic field is a force field acting on moving charged particles. The size of the magnetic field depends on the rate of its change. According to this feature, two types of magnetic field are distinguished: dynamic and gravitational.

The gravitational magnetic field arises only near elementary particles and is formed depending on the features of their structure. The sources of a dynamic magnetic field are moving electric charges or charged bodies, conductors with current, as well as magnetized substances.

Magnetic field properties

The great French scientist André Ampere managed to find out two fundamental properties of the magnetic field:

1. The main difference between a magnetic field and an electric field and its main property is that it is relative. If you take a charged body, leave it motionless in any frame of reference, and place a magnetic needle nearby, it will, as usual, point north. That is, it will not detect any field other than the earth's. If you start moving this charged body relative to the arrow, then it will begin to turn - this indicates that when the charged body moves, a magnetic field also arises, in addition to the electric one. Thus, a magnetic field appears if and only if there is a moving charge.
2. The magnetic field acts on another electric current. So, you can detect it by tracing the movement of charged particles - in a magnetic field they will deviate, conductors with current will move, the frame with current will turn, magnetized substances will shift. Here we should recall the magnetic compass needle, usually painted in Blue colour- it's just a piece of magnetized iron. It always points north because the Earth has a magnetic field. Our entire planet is a huge magnet: at the North Pole there is a south magnetic belt, and at the South geographic pole is the north magnetic pole.

In addition, the properties of the magnetic field include the following characteristics:

1. The strength of the magnetic field is described by magnetic induction - this is a vector quantity that determines the strength with which the magnetic field affects moving charges.
2. The magnetic field can be of constant and variable type. The first is generated by an electric field that does not change in time, the induction of such a field is also unchanged. The second is most often generated using inductors powered by alternating current.
3. The magnetic field cannot be perceived by the human senses and is recorded only by special sensors.

Good day, today you will find out what is a magnetic field and where does it come from.

Every person on the planet at least once, but kept magnet in hand. Starting from souvenir fridge magnets, or working magnets for collecting iron pollen and much more. As a child, it was a funny toy that stuck to black metal, but not to other metals. So what is the secret of the magnet and its magnetic field.

What is a magnetic field

At what point does a magnet begin to attract towards itself? Around each magnet there is a magnetic field, getting into which, objects begin to be attracted to it. The size of such a field may vary depending on the size of the magnet and its own properties.

Wikipedia term:

Magnetic field - a force field acting on moving electric charges and on bodies with a magnetic moment, regardless of the state of their movement, the magnetic component of the electromagnetic field.

Where does the magnetic field come from

The magnetic field can be created by the current of charged particles or by the magnetic moments of electrons in atoms, as well as by the magnetic moments of other particles, although to a much lesser extent.

Manifestation of a magnetic field

The magnetic field manifests itself in the effect on the magnetic moments of particles and bodies, on moving charged particles or conductors with . The force acting on an electrically charged particle moving in a magnetic field is called the Lorentz force, which is always directed perpendicular to the vectors v and B. It is proportional to the charge of the particle q, the component of the velocity v, perpendicular to the direction of the magnetic field vector B, and the magnitude of the magnetic field induction B.

What objects have a magnetic field

We often do not think about it, but many (if not all) of the objects around us are magnets. We are used to the fact that a magnet is a pebble with a pronounced force of attraction towards itself, but in fact, almost everything has an attraction force, it is just much lower. Let's take at least our planet - we do not fly away into space, although we do not hold on to the surface with anything. The field of the Earth is much weaker than the field of a pebble magnet, therefore it keeps us only due to its huge size - if you have ever seen people walking on the Moon (which is four times smaller in diameter), you will clearly understand what we are talking about . The attraction of the Earth is based largely on the metal components. Its crust and core - they have a powerful magnetic field. You may have heard that near large deposits of iron ore, compasses stop showing the right direction to the north - this is because the principle of the compass is based on the interaction of magnetic fields, and iron ore attracts his arrow.