On the Internet, there are a lot of topics devoted to the study 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 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 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 spirals from 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 of a simple magnet is a potential system of local imbalance 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 is like an "ignition key" in this local system, includes an imbalance. AT this moment I carefully study 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, similar to the layers of Jupiter, which move in different sides. 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 every living being, in its essence, is the same localized imbalance, then 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 the fluid motion geometry depends on the time of day, season, solar activity, experimenter's intention, 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 "...

It is a force field that acts on electric charges and on bodies that are in motion and have a magnetic moment, regardless of the state of their movement. The magnetic field is part of the electromagnetic field.

The current of charged particles or the magnetic moments of electrons in atoms create a magnetic field. Also, a magnetic field arises as a result of certain temporal changes in the electric field.

The magnetic field induction vector B is the main power characteristic of the magnetic field. In mathematics, B = B (X,Y,Z) is defined as a vector field. This concept serves to define and specify the physical magnetic field. In science, the vector of magnetic induction is often simply, for brevity, called the magnetic field. Obviously, such an application allows some free interpretation of this concept.

Another characteristic of the magnetic field of the current is the vector potential.

It is often found in the scientific literature that as main characteristic magnetic field, in the absence of a magnetic medium (vacuum), the vector of the magnetic field strength is considered. Formally, this situation is quite acceptable, since in vacuum the magnetic field strength vector H and the magnetic induction vector B coincide. At the same time, the magnetic field strength vector in a magnetic medium is not filled with the same physical meaning, and is a secondary quantity. Based on this, with the formal equality of these approaches for vacuum, the systematic point of view considers magnetic induction vector the main characteristic of the current magnetic field.

The magnetic field, of course, is a special kind of matter. With the help of this matter, there is an interaction between having a magnetic moment and moving charged particles or bodies.

The special theory of relativity considers magnetic fields as a consequence of the existence of electric fields themselves.

Together, magnetic and electric fields form an electromagnetic field. The manifestations of the electromagnetic field are light and electromagnetic waves.

The quantum theory of the magnetic field considers the magnetic interaction as a separate case of the electromagnetic interaction. It is carried by a massless boson. A boson is a photon - a particle that can be represented as a quantum excitation of an electromagnetic field.

The magnetic field is generated either by the current of charged particles, or by the electric field transforming in time space, or by the intrinsic magnetic moments of the particles. The magnetic moments of particles for uniform perception are formally reduced to electric currents.

Calculation of the value of the magnetic field.

Simple cases allow us to calculate the values ​​of the magnetic field of a conductor with current according to the Biot-Savart-Laplace law, or using the circulation theorem. In the same way, the value of the magnetic field can also be found for a current arbitrarily distributed in a volume or space. Obviously, these laws are applicable for constant or relatively slowly changing magnetic and electric fields. That is, in cases of presence of magnetostatics. More difficult cases require value calculation magnetic field current according to Maxwell's equations.

Manifestation of the presence of a magnetic field.

The main manifestation of the magnetic field is the effect on the magnetic moments of particles and bodies, on charged particles in motion. Lorentz force called the force that acts on an electrically charged particle that moves in a magnetic field. This force has a constant perpendicular direction to the vectors v and B. It also has a proportional value to the charge of the particle q, the component of the velocity v, which is perpendicular to the direction of the magnetic field vector B, and the quantity that expresses the magnetic field induction B. The Lorentz force according to the International System of Units has this expression: F=q, in the CGS system of units: F=q/c

The vector product is displayed in square brackets.

As a result of the influence of the Lorentz force on charged particles moving along the conductor, the magnetic field can also act on the current-carrying conductor. The ampere force is the force acting on a current-carrying conductor. The components of this force are the forces acting on individual charges that move inside the conductor.

The phenomenon of the interaction of two magnets.

The phenomenon of the magnetic field, which we can meet in Everyday life, is called the interaction of two magnets. It is expressed in the repulsion of identical poles from each other and the attraction of opposite poles. From a formal point of view, describing the interactions between two magnets as the interaction of two monopoles is a rather useful, feasible and convenient idea. At the same time, a detailed analysis shows that in reality this is not a completely correct description of the phenomenon. The main unanswered question in such a model is why the monopoles cannot be separated. Actually, it has been experimentally proved that any isolated body does not have a magnetic charge. Also, this model cannot be applied to a magnetic field created by a macroscopic current.

From our point of view, it is correct to assume that the force acting on a magnetic dipole located in an inhomogeneous field tends to turn it in such a way that the magnetic moment of the dipole has the same direction as the magnetic field. However, there are no magnets that are subject to the total force from uniform magnetic field current. The force that acts on a magnetic dipole with a magnetic moment m is expressed by the following formula:

.

The force acting on the magnet from an inhomogeneous magnetic field is expressed as the sum of all the forces that are determined by this formula and acting on the elementary dipoles that make up the magnet.

Electromagnetic induction.

In the case of a change in time of the flow of the magnetic induction vector through a closed circuit, an EMF of electromagnetic induction is formed in this circuit. If the circuit is stationary, it is generated by a vortex electric field, which arises as a result of the change in the magnetic field over time. When the magnetic field does not change with time and there is no change in flux due to the movement of the conductor loop, then the EMF is generated by the Lorentz force.

We still remember about the magnetic field from school, that's just what it is, "pops up" in the memories of not everyone. Let's refresh what we've been through, and maybe tell you something new, useful and interesting.

Determination of the magnetic field

A magnetic field is a force field that acts on moving electric charges (particles). Due to this force field, objects are attracted to each other. There are two types of magnetic fields:

1. Gravitational - is formed exclusively near elementary particles and viruetsya in its strength based on the features and structure of these particles.
2. Dynamic, produced in objects with moving electric charges (current transmitters, magnetized substances).

For the first time, the designation of the magnetic field was introduced by M. Faraday in 1845, although its meaning was a little erroneous, since it was believed that both electric and magnetic effects and interactions are based on the same material field. Later in 1873, D. Maxwell “presented” the quantum theory, in which these concepts began to be separated, and the previously derived force field was called the electromagnetic field.

How does a magnetic field appear?

Magnetic fields are not perceived by the human eye different items, and only special sensors can fix it. The source of the appearance of a magnetic force field on a microscopic scale is the movement of magnetized (charged) microparticles, which are:

• ions;
• electrons;
• protons.

Their movement occurs due to the spin magnetic moment, which is present in each microparticle.

Magnetic field, where can it be found?

No matter how strange it may sound, but almost all objects around us have their own magnetic field. Although in the concept of many, only a pebble called a magnet has a magnetic field, which attracts iron objects to itself. In fact, the force of attraction is in all objects, it only manifests itself in a lower valence.

It should also be clarified that the force field, called magnetic, appears only under the condition that electric charges or bodies are moving.

Immovable charges have an electric force field (it can also be present in moving charges). It turns out that the sources of the magnetic field are:

• permanent magnets;
• mobile charges.

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

Magnetic field properties:

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 of measurement 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 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 Ampère 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 of measurement– 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 Araday recorded electric current in a circuit that did not contain a source, but was located next to another circuit 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[AT].

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 of measurement 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:
.

AT 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. This means that the energy at any moment of time is equal to either the maximum energy of the 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 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.

The magnetic field is special form matter that is created by magnets, conductors with current (moving charged particles) and which can be detected by the interaction of magnets, conductors with current (moving charged particles).

Oersted's experience

The first experiments (carried out in 1820), which showed that between electric and magnetic phenomena there is a deep connection, there were experiments by the Danish physicist H. Oersted.

A magnetic needle located near the conductor rotates through a certain angle when the current is turned on in the conductor. When the circuit is opened, the arrow returns to its original position.

It follows from the experience of G. Oersted that there is a magnetic field around this conductor.

Ampère experience
Two parallel conductors, through which an electric current flows, interact with each other: they attract if the currents are in the same direction, and repel if the currents are in the opposite direction. This is due to the interaction of the magnetic fields that arise around the conductors.

Magnetic field properties

1. Materially, i.e. exists independently of us and our knowledge of it.

2. Created by magnets, conductors with current (moving charged particles)

3. Detected by the interaction of magnets, conductors with current (moving charged particles)

4. Acts on magnets, conductors with current (moving charged particles) with some force

5. There are no magnetic charges in nature. You cannot separate the north and south poles and get a body with one pole.

6. The reason why bodies have magnetic properties was found by the French scientist Ampère. Ampere put forward the conclusion that the magnetic properties of any body are determined by closed electric currents inside it.

These currents represent the movement of electrons in orbits in the atom.

If the planes in which these currents circulate are located randomly with respect to each other due to the thermal motion of the molecules that make up the body, then their interactions are mutually compensated and the body does not exhibit any magnetic properties.

And vice versa: if the planes in which the electrons rotate are parallel to each other and the directions of the normals to these planes coincide, then such substances enhance the external magnetic field.

7. Magnetic forces act in a magnetic field along certain areas which are called magnetic lines of force. With their help, you can conveniently and clearly show the magnetic field in a particular case.

In order to depict the magnetic field more accurately, we agreed in those places where the field is stronger, to show the lines of force located more densely, i.e. closer friend to friend. And vice versa, in places where the field is weaker, field lines are shown in a smaller number, i.e. less frequently located.

8. The magnetic field characterizes the vector of magnetic induction.

The magnetic induction vector is a vector quantity that characterizes the magnetic field.

The direction of the magnetic induction vector coincides with the direction of the north pole of a free magnetic needle at a given point.

The direction of the field induction vector and the current strength I are related by the “rule of the right screw (gimlet)”:

if you screw the gimlet in the direction of the current in the conductor, then the direction of the speed of movement of the end of its handle at a given point will coincide with the direction of the magnetic induction vector at this point.

/ a magnetic field

Subject: Magnetic field

Prepared by: Baigarashev D.M.

Checked by: Gabdullina A.T.

A magnetic field

If two parallel conductors are connected to a current source so that an electric current passes through them, then, depending on the direction of the current in them, the conductors either repel or attract.

The explanation of this phenomenon is possible from the standpoint of the appearance around the conductors of a special type of matter - a magnetic field.

The forces with which current-carrying conductors interact are called magnetic.

A magnetic field- this is a special kind of matter, a specific feature of which is the action on a moving electric charge, conductors with current, bodies with a magnetic moment, with a force depending on the charge velocity vector, the direction of the current strength in the conductor and on the direction of the magnetic moment of the body.

The history of magnetism goes back to ancient times, to ancient civilizations Asia Minor. It was on the territory of Asia Minor, in Magnesia, that they found rock, samples of which are attracted to each other. According to the name of the area, such samples began to be called "magnets". Any magnet in the form of a rod or a horseshoe has two ends, which are called poles; it is in this place that its magnetic properties are most pronounced. If you hang a magnet on a string, one pole will always point north. The compass is based on this principle. The north-facing pole of a free-hanging magnet is called the magnet's north pole (N). The opposite pole is called the south pole (S).

Magnetic poles interact with each other: like poles repel, and unlike poles attract. Similarly, the concept of an electric field surrounding an electric charge introduces the concept of a magnetic field around a magnet.

In 1820, Oersted (1777-1851) discovered that a magnetic needle located next to an electrical conductor deviates when current flows through the conductor, that is, a magnetic field is created around the current-carrying conductor. If we take a frame with current, then the external magnetic field interacts with the magnetic field of the frame and has an orienting effect on it, i.e., there is a position of the frame at which the external magnetic field has a maximum rotating effect on it, and there is a position when the torque force is zero.

The magnetic field at any point can be characterized by the vector B, which is called magnetic induction vector or magnetic induction at the point.

Magnetic induction B is a vector physical quantity, which is a force characteristic of the magnetic field at a point. It is equal to the ratio of the maximum mechanical moment of forces acting on a loop with current placed in a uniform field to the product of the current strength in the loop and its area:

The direction of the magnetic induction vector B is taken to be the direction of the positive normal to the frame, which is related to the current in the frame by the rule of the right screw, with a mechanical moment equal to zero.

In the same way as the lines of electric field strength are depicted, the lines of magnetic field induction are depicted. The line of induction of the magnetic field is an imaginary line, the tangent to which coincides with the direction B at the point.

The directions of the magnetic field at a given point can also be defined as the direction that indicates

the north pole of the compass needle placed at that point. It is believed that the lines of induction of the magnetic field are directed from the north pole to the south.

The direction of the lines of magnetic induction of the magnetic field created by an electric current that flows through a straight conductor is determined by the rule of a gimlet or a right screw. The direction of rotation of the screw head is taken as the direction of the lines of magnetic induction, which would ensure its translational movement in the direction of the electric current (Fig. 59).

where n 01 = 4 Pi 10-7V s / (A m). - magnetic constant, R - distance, I - current strength in the conductor.

Unlike electrostatic field lines, which start at a positive charge and end at a negative one, magnetic field lines are always closed. No magnetic charge similar to electric charge was found.

One tesla (1 T) is taken as a unit of induction - the induction of such a homogeneous magnetic field in which a maximum torque of 1 N m acts on a frame with an area of ​​1 m2, through which a current of 1 A flows.

The induction of a magnetic field can also be determined by the force acting on a current-carrying conductor in a magnetic field.

A conductor with current placed in a magnetic field is subjected to the Ampère force, the value of which is determined by the following expression:

where I is the current strength in the conductor, l- the length of the conductor, B is the modulus of the magnetic induction vector, and is the angle between the vector and the direction of the current.

The direction of the Ampere force can be determined by the rule of the left hand: the palm of the left hand is positioned so that the lines of magnetic induction enter the palm, four fingers are placed in the direction of the current in the conductor, then the bent thumb shows the direction of the Ampere force.

Considering that I = q 0 nSv and substituting this expression into (3.21), we obtain F = q 0 nSh/B sin a. The number of particles (N) in a given volume of the conductor is N = nSl, then F = q 0 NvB sin a.

Let us determine the force acting from the side of the magnetic field on a separate charged particle moving in a magnetic field:

This force is called the Lorentz force (1853-1928). The direction of the Lorentz force can be determined by the rule of the left hand: the palm of the left hand is positioned so that the lines of magnetic induction enter the palm, four fingers show the direction of movement of the positive charge, the thumb bent shows the direction of the Lorentz force.

The force of interaction between two parallel conductors, through which currents I 1 and I 2 flow, is equal to:

where l- the part of a conductor that is in a magnetic field. If the currents are in the same direction, then the conductors are attracted (Fig. 60), if the opposite direction, they are repelled. The forces acting on each conductor are equal in magnitude, opposite in direction. Formula (3.22) is the main one for determining the unit of current strength 1 ampere (1 A).

The magnetic properties of a substance are characterized by a scalar physical quantity - magnetic permeability, which shows how many times the induction B of a magnetic field in a substance that completely fills the field differs in absolute value from the induction B 0 of a magnetic field in vacuum:

According to their magnetic properties, all substances are divided into diamagnetic, paramagnetic and ferromagnetic.

Consider the nature of the magnetic properties of substances.

Electrons in the shell of atoms of matter move in different orbits. For simplicity, we consider these orbits to be circular, and each electron revolving around the atomic nucleus can be considered as a circular electric current. Each electron, like a circular current, creates a magnetic field, which we will call orbital. In addition, an electron in an atom has its own magnetic field, called the spin field.

If, when introduced into an external magnetic field with induction B 0, induction B is created inside the substance< В 0 , то такие вещества называются диамагнитными (n 1).

In diamagnetic materials, in the absence of an external magnetic field, the magnetic fields of electrons are compensated, and when they are introduced into a magnetic field, the induction of the magnetic field of an atom becomes directed against the external field. The diamagnet is pushed out of the external magnetic field.

At paramagnetic materials, the magnetic induction of electrons in atoms is not fully compensated, and the atom as a whole turns out to be like a small permanent magnet. Usually in matter all these small magnets are oriented arbitrarily, and the total magnetic induction of all their fields is equal to zero. If you place a paramagnet in an external magnetic field, then all small magnets - atoms will turn in the external magnetic field like compass needles and the magnetic field in the substance increases ( n >= 1).

ferromagnetic are materials that are n"1. So-called domains, macroscopic regions of spontaneous magnetization, are created in ferromagnetic materials.

In different domains, the induction of magnetic fields has different directions (Fig. 61) and in a large crystal

mutually compensate each other. When a ferromagnetic sample is introduced into an external magnetic field, the boundaries of individual domains are shifted so that the volume of domains oriented along the external field increases.

With an increase in the induction of the external field B 0, the magnetic induction of the magnetized substance increases. For some values ​​of B 0, the induction stops its sharp growth. This phenomenon is called magnetic saturation.

A characteristic feature of ferromagnetic materials is the phenomenon of hysteresis, which consists in the ambiguous dependence of the induction in the material on the induction of the external magnetic field as it changes.

The magnetic hysteresis loop is a closed curve (cdc`d`c), expressing the dependence of the induction in the material on the amplitude of the induction of the external field with a periodic rather slow change in the latter (Fig. 62).

The hysteresis loop is characterized by the following values ​​B s , B r , B c . B s - the maximum value of the induction of the material at B 0s ; B r - residual induction, equal to the value of the induction in the material when the induction of the external magnetic field decreases from B 0s to zero; -B c and B c - coercive force - a value equal to the induction of the external magnetic field necessary to change the induction in the material from residual to zero.

For each ferromagnet, there is such a temperature (Curie point (J. Curie, 1859-1906), above which the ferromagnet loses its ferromagnetic properties.

There are two ways to bring a magnetized ferromagnet into a demagnetized state: a) heat above the Curie point and cool; b) magnetize the material with an alternating magnetic field with a slowly decreasing amplitude.

Ferromagnets with low residual induction and coercive force are called soft magnetic. They find application in devices where a ferromagnet has to be frequently remagnetized (cores of transformers, generators, etc.).

Magnetically hard ferromagnets, which have a large coercive force, are used for the manufacture of permanent magnets.

DETERMINATION OF THE INDUCTION OF THE MAGNETIC FIELD ON THE AXIS OF THE CIRCULAR CURRENT

Objective : to study the properties of a magnetic field, to get acquainted with the concept of magnetic induction. Determine the induction of the magnetic field on the axis of the circular current.

Theoretical introduction. A magnetic field. The existence of a magnetic field in nature is manifested in numerous phenomena, the simplest of which are the interaction of moving charges (currents), current and a permanent magnet, two permanent magnets. A magnetic field vector . This means that for its quantitative description at each point in space, it is necessary to set the vector of magnetic induction. Sometimes this quantity is simply called magnetic induction . The direction of the vector of magnetic induction coincides with the direction of the magnetic needle located at the considered point in space and free from other influences.

Since the magnetic field is a force field, it is depicted using lines of magnetic induction - lines, the tangents to which at each point coincide with the direction of the magnetic induction vector at these points of the field. It is customary to draw a number of lines of magnetic induction through a single area perpendicular to , equal to the value of magnetic induction. Thus, the line density corresponds to the value AT . Experiments show that there are no magnetic charges in nature. The consequence of this is that the lines of magnetic induction are closed. The magnetic field is called homogeneous if the induction vectors at all points of this field are the same, that is, they are equal in absolute value and have the same directions.

For a magnetic field, superposition principle: the magnetic induction of the resulting field created by several currents or moving charges is vector sum magnetic induction fields created by each current or moving charge.

In a uniform magnetic field, a straight conductor is acted upon ampere power:

where is a vector equal in absolute value to the length of the conductor l and coinciding with the direction of current I in this conductor.

The direction of the Ampère force is determined right screw rule(vectors , and form a right screw system): if a screw with a right-hand thread is placed perpendicular to the plane formed by the vectors and , and rotate it from to along the smallest angle, then the translational motion of the screw will indicate the direction of the force . In scalar form, relation (1) can be written as follows way:

F=I× l× B× sin a or (2).

From the last relation follows physical meaning of magnetic induction : the magnetic induction of a uniform field is numerically equal to the force acting on a conductor with a current of 1 A, 1 m long, located perpendicular to the direction of the field.

The SI unit for magnetic induction is Tesla (Tl): .

Magnetic field of circular current. An electric current not only interacts with a magnetic field, but also creates it. Experience shows that in a vacuum a current element creates a magnetic field with induction at a point in space

(3) ,

where is the coefficient of proportionality, m 0 \u003d 4p × 10-7 H / m is the magnetic constant, is a vector numerically equal to the length of the conductor element and coinciding in direction with the elementary current, is the radius vector drawn from the conductor element to the considered point of the field, r is the modulus of the radius vector. Relation (3) was experimentally established by Biot and Savart, analyzed by Laplace, and therefore is called Biot-Savart-Laplace law. According to the right screw rule, the magnetic induction vector at the considered point turns out to be perpendicular to the current element and the radius vector.

Based on the Biot-Savart-Laplace law and the principle of superposition, the calculation of the magnetic fields of electric currents flowing in conductors of arbitrary configuration is carried out by integrating over the entire length of the conductor. For example, the magnetic induction of the magnetic field in the center of a circular coil with a radius R through which current flows I , is equal to:

The lines of magnetic induction of circular and direct currents are shown in Figure 1. On the axis of the circular current, the line of magnetic induction is straight. The direction of magnetic induction is related to the direction of current in the circuit right screw rule. As applied to circular current, it can be formulated as follows: if a right-handed screw is rotated in the direction of the circular current, then the translational movement of the screw will indicate the direction of the magnetic induction lines, the tangents to which at each point coincide with the magnetic induction vector.

, (5)

where R is the radius of the ring, X is the distance from the center of the ring to the point on the axis at which the magnetic induction is determined.

What is the definition, magnetic field..??

Roger

In modern physics, the "Magnetic field" is considered as one of the force fields, leading to the action of a magnetic force on moving electric charges. A magnetic field is created by moving electric charges, usually electric currents, as well as an alternating electric field. There is a hypothesis about the possibility of the existence of magnetic charges, which, in principle, is not prohibited by electrodynamics, but so far such charges (magnetic monopoles) have not been discovered. Within the framework of Maxwell's electrodynamics, the magnetic field turned out to be closely related to the electric field, which led to the emergence of a single concept of the electromagnetic field.
Field physics somewhat changes the attitude to the magnetic field. First, it proves that magnetic charges cannot exist in principle. Secondly, the magnetic field turns out to be not an independent field, equal to the electric one, but one of the three dynamic corrections that arise during the movement of electric charges. Therefore, field physics considers only the electric field as fundamental, and the magnetic force becomes one of the derivatives of the electrical interaction.
P.S. the professor, of course, is a burdock, but the equipment is with him ....

Marie

Magnetic field - a component of the electromagnetic field that appears in the presence of a time-varying electric field. In addition, a magnetic field can be created by the current of charged particles, or by the magnetic moments of electrons in atoms (permanent magnets). The main characteristic of a magnetic field is its strength, which is determined by the magnetic induction vector \vec(\mathbf(B)). In SI, magnetic induction is measured in Tesla (T).
Physical properties
The magnetic field is formed by a time-varying electric field or intrinsic magnetic moments of the particles. In addition, the magnetic field can be created by the current of charged particles. In simple cases, it can be found from the Biot-Savart-Laplace law or the circulation theorem (it is also Ampère's law). In more difficult situations is sought as a solution to the Maxwell equations
The magnetic field manifests itself in the effect on the magnetic moments of particles and bodies, on moving charged particles (or conductors with current). The force acting on a charged particle moving in a magnetic field is called the Lorentz force. It is proportional to the charge of the particle and the vector product of the field and the velocity of the particle.
Mathematical representation
A vector quantity that forms a field with zero divergence in space.