UDC 538.566.2: 621.372.8

Surface electromagnetic waves on flat boundaries of electrically conductive media with high conductivity, Zenneck wave

V. V. Shevchenko
Institute of Radio Engineering and Electronics named after. V.A. Kotelnikov RAS

annotation. The properties of a theoretical model of surface electromagnetic waves directed by flat boundaries of highly conductive media: metals, wet soil, sea and generally salt water are considered. The phase, “group” and energy velocities of such waves are calculated. It is shown that these waves belong to an unusual type of waves, in which the “group” speed differs from the energy speed, i.e. the speed of energy transfer by the wave. And although, depending on the parameters of the medium, the phase and “group” velocities of such waves can be greater than the speed of light With, their energy speed is always less than the speed of light. The type of waves considered is the so-called Zenneck wave.

Keywords: surface waves; phase, group, energy wave speeds; Zenneck wave.

Abstract.The properties of a theoretical model of surface electromagnetic waves, guided by the plane boundaries of high conductive media: metals, humid soils, sea and salty water in general are considered. The phase,”group” and energy flow velocities of these waves are calculated. These waves are related to the unusual type of waves, the “group” velocity of which is differed from the energy flow velocity, that is the wave energy transport velocity. Although depending on average parameters the phase and “group” velocities of these waves can be more than the light velocity c, their energy flow velocity is always less than the light velocity c. So named Zenneck’s wave is related to considered the type of waves.

Key words: surface waves; phase, group, energy flow velocities of waves; Zenneck's wave.

Introduction

The question of the surface waves indicated in the title of the article and, in particular, the so-called Zenneck wave has been raised for many years from time to time in scientific discussions in the field of applied electrodynamics, both by theorists and experimentalists. Since such discussions are reflected in many publications (see, for example, in and references in them), here we do not dwell on the details of published statements and doubts. Let us only note that the following questions are usually discussed. Is the Zenneck wave even possible from a physical point of view: does this not contradict physical laws, and if it is possible, then can it be excited by physically feasible sources and can it be used for signal transmission in communication systems and radar.

The theoretical analysis presented below gives, in the author’s opinion, a very definite answer to at least the first two of these questions, i.e. does not contradict and you can excite her. The remaining question relates to the technology of implementation and application of such surface waves.

1. Basic properties of a surface wave on a flat boundary of a highly conductive medium

Let the dependence of a stationary electromagnetic field on time have the form , where is the circular frequency of the field. Let us consider for simplicity, as is usually done [,], a two-dimensional model (the results are easily transferred to a three-dimensional model) of an electromagnetic surface wave on a flat boundary (Fig. 1) between free space with parameters , and an electrically conductive non-magnetic () medium with an effective dielectric constant, where is the complex dimensionless relative permeability

. (1)

Rice. 1. Flat boundary of an electrically conductive medium

, . (2)

For example, for wet soil, sea and simply salt water () in the radio wave range, and for metals () in the radio wave range, microwave, EHF and up to the infrared optical frequency range

, (3)

Where is the specific conductivity of the medium.

Complex magnetic and electric components of the field of a surface wave of corresponding polarization propagating along the flat boundary of the medium in the direction of the axis z(Fig.2), represent it in the form

, (4)

, (5)

(6)

Where A– amplitude constant, , With - speed of light and- wavelength in free space, ,

, (7)

Rice. 2. Localization of the wave field near the boundary of the medium

The original dispersion equation obtained by matching the field at the boundary of the medium at y =0 according to equalities

. (10)

Approximate equation and its solution for look like

, (11)

,, (12)

and the refined equation and its solution for , i.e. according to (12) –

, . (13)

Based on these relations and expressions (), (), the values ​​are calculated

, (14)

. (15)

Thus, the wave is indeed a surface wave, since , , and it propagates along the boundary y =0 in the direction of the axis z.

It should be noted that result (15) can also be obtained from the relation

, (16)

(17)

which allows you to analyze the structure of the wave field corresponding to the expressions (), ().

Indeed, the quantity that describes the pressing of the wave field to the boundary of the medium, according to (16), increases the value of , which slows down the speed of movement of the phase front of the wave, and the quantity that describes the inclination of the phase front of the wave to the boundary of the medium (Fig. 3, the physical reason for the inclination is that that the medium partially absorbs the wave energy) reduces the value, that is, it accelerates the movement of the phase front of the wave along the boundary.

Fig.3. Inclination of the wave front to the boundary of the medium

Moreover, for the values ​​of these quantities corresponding to the expressions (), the terms with the highest small value in () are compensated, so that

, (18)

and as a result, only terms proportional to the square of this small quantity remain in the real part in (). The above-mentioned inclination of the direction of propagation of the phase front of the wave to the boundary of the medium (Fig. 3), according to what has been said, is a small angle

. (19)

Expressions (),(),() allow us to estimate the extent of the surface wave field in transverse (L y) and longitudinal ( Lz)directions that are approximately equal

(20)

Here, the small transverse extent of the wave field inside the medium is not taken into account, equal, according to ()

. (21)

(32)

It should be noted here that the transitions of the values ​​of the phase and group velocities of waves through the speed c occur under different environmental parameters. Considering the approximate nature of the introduced velocities, there is no reason to attach any physical meaning to the obtained specific values ​​of the transient parameters of the medium.

4. Energy speed

Energy speed, i.e. the speed of energy wave transmission [ , , ] can be calculated using the following formula specified here:

, (33)

where time-averaged is the longitudinal (along the z axis) flow of power transferred by the wave and is the linear energy density per unit length moved along with the wave along the guide structure, i.e. flat boundary (also along the z axis). This kinematically determined energy velocity is based on the Umov-Poynting theorem. It is applicable both to waves propagating without loss of energy and to waves with loss. This definition does not include dissipative and absorbed energy by the medium, which does not propagate with the wave. In this case, a balance is achieved between the energy transported by the wave along the boundary of the medium.

For the wave under consideration we have

, (34)

where and are partial power flows above and below the plane y =0, which according to (), () are equal

(35)

and correspondingly , where at m we have

(36)

(37)

. (43)

Based on this expression and formula (), we obtain for the surface waves considered here

, (44)

Where - phase, and at small values ​​it is also the energy velocity of a slow surface wave in the direction of movement of the phase front. As a result, based on () we get

. (45)

Essentially, the calculation made use of the property of waves with a plane phase front, applicable to plane and similar waves, which is that the inclination of the direction of motion of the phase front relative to the direction of wave propagation increases the phase velocity (), (), () and reduces the energy speed (45) of the wave.

As a result, we have that the energy speed of a surface wave is always less With, including the case corresponding to the Zenneck wave, for which the phase and group velocities are greater With.

5. Discussion of results

Let us discuss critically known versions, on the basis of which, it would seem, it can be argued that the theoretical model of surface waves discussed above does not describe physical surface waves directed by the boundary of an electrically conductive medium with high conductivity in the case when the phase and/or group velocities are greater than the speed of light With.

As follows from another, non-asymptotic, method of representing the total source field in the form of a spectral expansion in terms of natural waves (in transverse wave numbers with a discrete-continuous spectrum) of an open guide structure, here the boundaries of the medium [ , , ], such expansion in its original form contains, in addition to integral of a selected surface wave, regardless of whether it is slow or fast. This expansion can be obtained either directly on the basis of the theory of a singular (in an infinite interval) transverse boundary value problem on eigenvalues ​​and eigenfunctions [, ], or by transforming the indicated integral Fourier expansion in longitudinal wave numbers into an expansion in transverse wave numbers. In the second case, when the integration contour is deformed in the complex plane of wave numbers, this contour equally sweeps out the poles of the integrand corresponding to both slow and fast surface waves [ , , ]. Thus, the surface wave, both slow and fast, is contained in the total field excited by the source, but it attenuates and disappears in asymptotics, where only the space wave field remains.

Conclusion

The waves considered are a special type of surface waves, the surface nature of which, i.e. The exponential decay of the field from the boundary of the highly conductive medium under consideration in the transverse direction occurs here not because of the slowness of its phase velocity relative to the speed of plane waves above the boundary of the medium, which turned out to be unnecessary here, but because of the partial absorption of energy in it during wave propagation. The presented results show that the considered model of such surface waves does not contradict physical laws. Therefore, there is no reason to doubt that it describes physical waves and when their phase velocity is less c, and when – more, and the generally accepted “group” speed for them, apparently, does not have a clear physical meaning.

However, such waves have significant disadvantages from the point of view of their use in technical applications. Firstly, they are weakly pressed against the boundary of the medium, i.e. their field has a sufficiently large extent in the transverse direction above the boundary, so to effectively excite them may require a source with a vertical aperture that is too large. Secondly, their phase speed is only slightly different from the speed of light With, therefore, any, even small, irregularities in the plane of the boundary of the medium can lead to scattering of the wave field and a significant increase in energy losses when propagating along the boundary. In particular, this can occur when the boundary deviates from the plane, i.e. in the presence of curvature of its surface. Analysis of the considered surface waves on an irregular boundary requires special research [,].

On the other hand, when trying to apply surface waves, for example, at the boundaries of metals in technical applications, it is necessary to take into account that the surfaces of real metals are usually covered with oxide films having a thickness of the order of fractions of a micron, micron or several microns (natural films) and of the order of tens of microns (artificially created films for mechanical protection of metal surfaces). In this case, it is necessary to use the results of a slightly different theoretical model of the guiding system: a layered structure such as metal substrate - dielectric film (necessarily taking into account energy losses in them) - free space. The presence of a film can significantly affect the pressure of the surface wave in the direction of its increase and, consequently, the possibility of simplifying the excitation of the wave and its greater stability with respect to structure irregularities.

As an afterword to the article, we note that in September 2012, this article was submitted to the journal UFN, which had previously published a series of articles devoted to the Zenneck wave, and, in essence, a discussion arose on this topic. However, the article was not accepted for publication due to the fact that the editorial board of UFN decided “not to accept new work on Zenneck waves for consideration.” As a result of this, the indicated publication of articles on this topic in UFN actually ended with the publication of an erroneous article.

Literature

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2.Shevchenko V.V. // Radio engineering and electronics. 1969.T.14. No. 10.S.1768.

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17. Mandelstam L. I. Lectures on optics, relativity theory and quantum mechanics. M.: Nauka, 1972. P.420,431.

18. Zilbergleit A. S., Kopilevich Yu. I. // Letters to ZhTP. 1979.T.5.No.8. P. 454.

19. Brekhovskikh L. M. Waves in layered media. M.: Publishing house. USSR Academy of Sciences, 1957.

20.Barlow H. M., Brown J. Radio surface waves. Oxf.: Clarendon Press, 1962.

21. Shevchenko V.V.//Differential equations.1979.T.15. No. 11. WITH .2004 (ShevchenkoV.V.//Differential Equations.1980.V.15. No. 11.P.1431).

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1 Syomkin Sergey Viktorovich, Smagin Viktor Pavlovich ELECTROMAGNETIC EFFECTS CAUSED BY SEA SURFACE WAVES Article address: The article was published in the author's edition and reflects the point of view of the author(s) on this issue. Source Almanac of modern science and education Tambov: Certificate, (59). C ISSN Journal address: Contents of this issue of the journal: Publishing house "Gramota" Information about the possibility of publishing articles in the journal is posted on the publishing house's website: The editors ask questions related to the publication of scientific materials to be sent to:

2 194 Publishing house "Gramota" Fig. 3. Filling out competencies To develop an information system for accounting for objects of an intelligent system. The PHP programming language was chosen, since this programming language allows you to create dynamic web pages and link them to a database implemented in MySQL. This approach allows you to place the system on the Internet and access it from anywhere without additional software. The developed information system for recording intellectual property contributes to: - reducing the time spent on participation in the development and implementation of a unified patent and licensing policy of the organization; - redistribution of the workload of the organization’s employees; - increasing the efficiency of accounting and control over the registration of intellectual property and timely registration of reports on them. The information system for recording intellectual property objects allows for convenient and reliable storage and management of department data, the ability to prepare documents for filing an application for official registration of a computer program or database. This will significantly improve the quality of services for the protection and protection of intellectual property and increase the efficiency of work with intellectual property objects. References 1. All-Russian Scientific and Technical Information Center [Electronic resource]. URL: (access date:). 2. Intellectual property: trademark, invention, patenting, patent attorney, patent bureau, Rospatent [Electronic resource]. URL: (access date:). 3. Sergeev A.P. Intellectual property rights in the Russian Federation: textbook. M., p. 4. Federal Institute of Industrial Property [Electronic resource]. URL: (access date:). UDC Physical and mathematical sciences Sergey Viktorovich Semkin, Viktor Pavlovich Smagin Vladivostok State University of Economics and Service ELECTROMAGNETIC EFFECTS CAUSED BY SEA SURFACE WAVES 1. Introduction Sea water, as is known, is a conductive liquid due to the presence of ions of different signs in it. Its electrical conductivity, depending on temperature and salinity, can Syomkin S.V., Smagin V.P., 2012

3 ISSN Almanac of modern science and education, 4 (59) change on the ocean surface within 3-6 Sym/m. Macroscopic movements of seawater in a geomagnetic field can be accompanied by the emergence of electric currents, which, in turn, generate an additional magnetic field. This induced field is influenced by a number of different factors. Firstly, the type of hydrodynamic source - sea surface waves, internal waves, currents and tides, long waves such as tsunamis, etc. An induced electromagnetic field can also be created by other types of macroscopic water movement - acoustic waves and artificial sources - underwater explosions and ship waves. Secondly, this field can be influenced by the electrical conductivity of seafloor rocks and seafloor topography. It can also be noted that a problem similar to calculating the induced field in the marine environment also arises in seismology - the movement of the lithosphere in the Earth's magnetic field leads to the emergence of induced currents. One of the directions for studying the spatiotemporal structure of the induced field is the case when it is generated by a two-dimensional surface wave. The calculation of the electromagnetic field induced by a surface wave can be carried out in various approximations and for various models of the marine environment. The field induced by sea surface waves in the approximation of an infinitely deep ocean was calculated in the works, and in the work the fields induced by wind waves in shallow zones taking into account a finite variable depth were theoretically studied. A more complex hydrodynamic model of sea waves - vortex waves with a finite crest - was considered in. That is, a significant number of different options for formulating the problem are possible, depending on the influence of which factors need to be taken into account. In this work, we study the influence of the electrical and magnetic properties of bottom rocks, namely their magnetic permeability and electrical conductivity, on the induced electromagnetic field. Typically, the study of the influence of the properties of bottom rocks on the magnetic field is limited to taking into account only their electrical conductivity, since bottom rocks, as a rule, do not have pronounced magnetic properties. However, in the coastal zone of the ocean it is quite possible that the bottom rocks also have magnetic properties. In addition, it turns out [Ibid.] that for potential fluid movement, the occurrence of currents in bottom rocks is possible only due to induction effects - a term in Maxwell’s equations. And discarding this term (quasi-static approximation) leads to the fact that the induced field does not depend at all on the conductivity of bottom rocks. Therefore, we will consider this formulation of the problem of determining the electromagnetic field induced by a surface wave, in which the bottom has not only electrical conductivity, but also magnetic properties, and we will also take into account the effect of self-induction. 2. Basic equations and boundary conditions To solve the problem of determining the electromagnetic field induced by the movement of sea water in the geomagnetic field, the Maxwell system of equations is used: (1) The relationship between pairs of vectors and (material equations) as well as the expression for the current density are different in different media . We will assume that in air (medium I) the connection between the vectors characterizing the electromagnetic field is the same as in vacuum, and there are no electric currents and space charges: (2) We will consider sea water (medium II) to be homogeneous in both hydrodynamic and and electromagnetic properties. The material equations in the coordinate system relative to which the fluid moves are described in. Assuming that the speed of water movement is low, and the induced magnetic field is significantly less than the geomagnetic field, we obtain: , (3) (4) where and are the electrical permeability and conductivity of sea water. Let's consider the question of volumetric electric charges inside water. From equations (1), relation (3), Ohm's law (4) and the conditions for conservation of electric charge, we obtain: (5) For the case of a stationary process, when and, solution (5) has the form: where is the characteristic time for establishing a stationary state. At,. This means that any established hydrodynamic and hydroacoustic processes can be

4 196 Publishing House "Gramota" be considered steady in the electrodynamic sense. Since the cyclic frequencies do not even exceed ultrasonic waves, we can assume with good accuracy that Thus, with the potential movement of sea water (), there are no space charges in sea water. We will assume that bottom rocks (medium III) are a semi-infinite homogeneous medium with conductivity, dielectric and magnetic permeability and, respectively. The material equations and Ohm's law in this medium are as follows: (6) The volume density of electric charges in medium III obeys an equation similar to (5), but with a zero right-hand side. Therefore, in a stationary periodic mode. The characteristic time for establishing equilibrium is of the same order as. As shown in , the boundary conditions at boundaries I-II and II-III have the same form for low velocities of water movement as for stationary media. That is, at the boundary I-II:, (7) At the boundary II-III:, (8) The surface charge densities are not known in advance and are found when solving the problem. 3. Two-dimensional surface wave Consider a two-dimensional surface wave propagating in the direction of the axis (the axis is directed vertically upward, and the plane coincides with the undisturbed surface of the water). The velocities of liquid particles will be as follows:, (9) - sea depth., and are related by the dispersion relation (10) Let us introduce the angles and that determine the orientation of the geomagnetic field vector (in the original coordinate system) as follows: That is, is the angle between the vertical and the vector , depending on the latitude of the place, and is the angle between the direction of wave propagation and the projection of the vector onto the horizontal plane. We will look for a solution to system (1) in the form Substituting these expressions into (1), we obtain: (11) (12) (13) (14) (15) ( () (16) ( (17) ( () (18) Equations (11)-(18) can be divided into two groups: equations (11), (13), (16) and (18) for the components, and equations (12), (14), (15) and (17 ) for components, and. We solve the equations of the second group as follows and express them through: and the equations for have the form Here,. Finding the general solution (20) and using (19), we obtain in environment I: (19) (20)

5 ISSN Almanac of modern science and education, 4 (59) in environment II:, (21) (22) in environment III:, (23) To determine the coefficients, and we use the boundary conditions (7) and (8) Excluding and, we reduce system to two equations for and which we write in matrix form: () () () Solving this system, we find the coefficients and through which the components of the electromagnetic field are expressed, and. In a similar way, we solve the system of equations (11), (13), (16) and (18) for the components, and the equations for have the form The component is expressed from (19). Solving (25) and using (23) and (19) we find the components in medium I: in medium II: (24) (25) (26) (27) in medium III: Using boundary conditions (7) and (8), we get: (28) Hence and. Thus, in all three media and ( (29) ( (30) The component has discontinuities at the boundaries between the media. This means that there are surface charges at the boundaries, the densities of which are determined from conditions (7) and (8): (boundary I -II) (31) (boundary II-III) (32) From the obtained solution it follows that the current density components and are equal to zero in all three media, which is consistent with the condition of conservation of electric charge. The component and is not equal to zero.

6 198 Publishing House "Gramota" in order of magnitude is. The existence of periodically changing surface charges at first glance contradicts the condition: since the medium is not superconducting, there are no surface currents, and a change in the surface charge can only be associated with the existence of a volume current component normal to the boundary. We will find the value of this component from the condition of charge conservation. Thus, the ratio will be of the order that for sea water and typical frequencies of wind waves is approximately. That is, when discarding, we do not go beyond the accuracy with which the material equations (2), (4) and (6) and boundary conditions (7) and (8) are considered. 4. Calculation results and conclusions Thus, for a two-dimensional surface wave having an arbitrary direction relative to the magnetic meridian, we calculated the components of the magnetic and electric fields in all media, as well as surface electric charges on the bottom and free surface. The influence of the electrical and magnetic properties of bottom rocks on the wave-induced magnetic field is manifested as follows. Rice. 1 In Fig. Figure 1 shows the dependences of the amplitudes of the components equal above the surface and (in units) on the wave period for waves of the same amplitude. Curve 2 corresponds to the case of a non-magnetic and non-conducting bottom (,), curve 1 to the case of a non-magnetic conducting bottom (,), curve 4 to the case of a magnetic non-conducting bottom (,), and curve 3 to the case of a magnetic conducting bottom (,). All curves are calculated for the case. It turns out that for any value of the wave period, the induced field monotonically increases with increasing magnetic permeability of the bottom and decreases with increasing its conductivity. The dependence of the magnetic field on the wave period can be either monotonically increasing or having a maximum, depending on the orientation of the wave relative to the geomagnetic field. Rice. 2

7 ISSN Almanac of modern science and education, 4 (59) In Fig. Figure 2 shows the dependences of the induced magnetic field (in the same units as in Fig. 1) on the sea depth (in kilometers) for waves with a period of,. Curves 1, 2, 3 and 4 correspond to values ​​equal to 1, 2, 10 and 100. From the results obtained, the following general conclusions can be drawn: 1. Volumetric electric charges do not arise either in sea water or in conductive bottom rocks in the case of potential motion sea ​​water. 2. Surface electric charges (30), (31) are determined only by the component of the geomagnetic field, the amplitude and frequency of the wave and the depth of the ocean and do not depend on the magnetic permeability and electrical conductivity of bottom rocks and sea water. 3. The along-ridge component of the induced magnetic field is zero in all media. 4. The along-ridge component of the induced electric field is zero in the quasi-static approximation, and the and components, like surface electric charges, do not depend on the electrical and magnetic properties of water and bottom rocks. 5. For all values ​​of ocean depth and wave period, the magnitude of the induced magnetic field monotonically increases to a final limit value with increasing magnetic permeability of bottom rocks and monotonically decreases with increasing their conductivity. References 1. Gorskaya E. M., Skrynnikov R. T., Sokolov G. V. Magnetic field variations induced by the movement of sea waves in shallow water // Geomagnetism and Aeronomy S. Guglielmi A. V. Ultra-low-frequency electromagnetic waves in the Earth’s crust and magnetosphere // UFN TS Sommerfeld A. Electrodynamics. M., Savchenko V.N., Smagin V.P., Fonarev G.A. Issues of marine electrodynamics. Vladivostok: VGUES, p. 5. Semkin S.V., Smagin V.P., Savchenko V.N. Magnetic field of an infrasonic wave in an oceanic waveguide // Geomagnetism and Aeronomy T S Semkin S.V., Smagin V.P., Savchenko V.N. Generation of magnetic field disturbances during an underwater explosion // Izvestia RAS. Physics of the atmosphere and ocean T S Smagin V. P., Semkin S. V., Savchenko V. N. Electromagnetic fields induced by ship waves // Geomagnetism and Aeronomy T S Sretensky L. N. Theory of wave motions of fluid. M.: Science, p. 9. Fonarev G. A., Semenov V. Yu. Electromagnetic field of sea surface waves // Study of the geomagnetic field in the waters of the seas and oceans. M.: IZMIRAN, S Fraser D. C. The Magnetic Fields of Ocean Waves // Geophys. Journal Royal Astron. Soc Vol P Larsen J. C. Electric and Magnetic Fields Induced by Deep Sea Tides // Geophys. Journal Royal Astron. Soc Vol. 16. P Pukhtyar L. D., Kukushkin A. S. Investigation of the Electromagnetic Fields Induced by Sea Motion // Physical Oceanography Vol P Sanford T. B. Motionally Induced Electric and Magnetic Fields in the Sea // J. Geophys. Res Vol P Warburton F., Caminiti R. The Induced Magnetic Field of Sea Waves // J. Geophys. Res Vol P Weaver J. T. Magnetic Variation Associated with Ocean Waves and Swell // J. Geophys. Res Vol P UDC 34 Legal sciences Victoria Vitalievna Sidorenko, Aigul Sharifovna Galimova Bashkir State University THE PROBLEM OF EFFECTIVENESS OF USE OF WORKING TIME Working time is an important category in the organization of labor in an enterprise. It represents the time during which the employee, in accordance with the internal labor regulations and the terms of the employment contract, must perform labor duties, as well as other periods of time that, in accordance with laws and other legal acts, relate to working time. Working time is a natural measure of labor, existing at the same time as a multifaceted category, because The general health and vital activity of a person depends on the length of working hours. The duration and intensity of working time directly affects the length of rest time a person needs to recuperate, expend energy, fulfill family responsibilities for education, etc. Therefore, the strictest compliance with working time legislation is at the same time ensuring the most important constitutional human right - the right to rest. Regulation of working hours solves such important problems as: establishing the possible participation of citizens in public labor, ensuring labor protection, and ensuring the right to rest. Sidorenko V.V., Galimova A.Sh., 2012

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Introduction

History of long and short wave research

Propagation of shortwave waves

General properties of radio waves.

Propagation of surface (ground) radio waves.

Propagation of spatial radio waves.

Propagation of myriameter and kilometer waves (ultra-long and long)

Propagation of hectometer (average) waves.

Propagation of decameter (short) waves.

Propagation of waves shorter than 10 m (VHF and microwave waves)

Conclusion

Bibliography

Introduction

Like light waves, radio waves can travel long distances in the Earth's atmosphere with virtually no loss, making them useful carriers of encoded information.

After the appearance of Maxwell's equations, it became clear that they predict the existence of a natural phenomenon unknown to science - transverse electromagnetic waves, which are oscillations of interconnected electric and magnetic fields propagating in space at the speed of light. James Clark Maxwell himself was the first to point out to the scientific community this consequence from the system of equations he derived. In this refraction, the speed of propagation of electromagnetic waves in a vacuum turned out to be such an important and fundamental universal constant that it was designated by a separate letter c, in contrast to all other speeds, which are usually designated by the letter v.

In the 20th century, electromagnetic waves began to firmly enter people's lives. Even before the war, radio sets appeared in the apartments of city residents, then televisions, which became unusually widespread in the 60s. In the 90s, radiotelephones, microwave ovens, remote controls for televisions, VCRs, etc. began to penetrate into our everyday life. All these devices emit or receive electromagnetic waves.

History of long and short wave research

electromagnetic radio wave range length

Radio waves include electromagnetic waves, the frequency of which is in the range of up to 3000 GHz = 3·1012 Hz. As can be seen from the figure below, they occupy a very modest part among the types of electromagnetic radiation known to us.

To date, humanity has learned to use electromagnetic waves up to the ultraviolet range to transmit information.

As you know, the development of radio waves began with the experiments of G. Hertz. He conducted his experiments on waves up to 67 cm long and proved that they have the same properties as light. In the wireless telegraphy systems practically implemented by A.S. Popov and G. Marconi, longer waves were used. This was done intuitively: to increase the range it was necessary to emit high-power electromagnetic oscillations. Greater power could only be obtained from larger antennas, and large antennas could only emit long wavelengths.

First of all, the fleet needed wireless communications. The size of the antenna on a ship was limited by the height of the masts and the distance between them. Therefore, waves with a length of 150 - 200 m were used for communication. Coastal stations had taller and much more spaced masts and therefore used waves up to 1000 m.

The increase in range occurred very quickly, and not only within line of sight. Marconi achieved particularly impressive results. The company he formed, Wireless Telegraph and Signal Company Limited, had sufficient funds, many well-known specialists of that time worked there, and Marconi himself was distinguished by his irrepressible energy.

In 1896, he demonstrated equipment with a communication range of 3 km. A year later they achieved a communication range of 21 km. In another year and a half – 70 km. At the beginning of 1901 - 300 km. And in December 1901 G. Marconi established a connection between England and North America at a distance of about 3,700 km. The energy that Marconi developed in promoting radio communications can be judged by the fact that he crossed the Atlantic Ocean eighty times.

The transmitting antenna (Fig. above), providing long-distance communication, occupied many hundreds of meters. The receiving antenna was a long wire attached to a balloon. In general, in long-distance communication lines, various antennas were then used at the receiving end, for example, a rhombic one, as shown in the figure below.

You can judge the size of this antenna by comparing it with the size of the furniture in the utility room on the first floor.

Two years later, communication was established with South America (10,000 km). The figure below shows how the achieved communication range has changed over the years.

But how electromagnetic waves passed to the other side of the Earth was completely unclear. At the beginning of their experiments, both Popov and Marconi assumed that radio waves, like light, propagate in a straight line. However, the connection established by G. Marconi on December 12, 1901 between New Foundland (Canada) and southwestern England (distance 3,700 km) forced researchers to abandon the idea of ​​​​the linear propagation of radio waves.

This fact was far from being explained, and experience showed that to achieve greater range, a longer wavelength was required. And in the second decade of the twentieth century, they began to build stations for transatlantic communications with a power of hundreds of kilowatts, on waves with a length of up to 15,000 - 20,000 m. The development curve for the long radio wave range is shown below. By 1920, the wavelength reached 30,000 m and its further growth stopped. On the one hand, this was explained by the fact that antenna systems were becoming too bulky. On the other hand, the low frequency of the electromagnetic wave (oscillation frequency with wavelength λ = 30,000 m is equal to f = c/λ = 3*108/3*104 = 104 Hz = 10 kHz) allowed the transmission of only low-frequency messages.

And the need for radio communications was increasing. Therefore, they were forced to master high-frequency ranges.

But one circumstance got in the way. It was experimentally established that short waves (shorter than 200 m) propagated in a straight line and did not go around the Earth, and were not suitable for communication over long distances. Therefore, they were considered unsuitable for long-distance communication and were given to radio amateurs. And radio amateurs were happy about this range and soon outdid the professionals. In 1921 - 1923 Radio amateurs in America and Europe blocked the Atlantic Ocean on these waves, with low transmitter power, and then established communications between the antipodean continents.

The amateur radio movement, having barely emerged, was marked by a fundamental discovery: short-wave radio communications, carried out by transmitters with a power of a few watts, arose and remained stable for a noticeable time at ranges inaccessible to radio stations operating in the long-wave range, although the power of the latter reached hundreds of kilowatts. This fact, unprecedented in the history of science, attracted the attention of many specialists to short waves, and their study began everywhere.

• Specialty of the Higher Attestation Commission of the Russian Federation01.04.03
• Number of pages 155

Part I. SLOW SURFACE MAGNETO-PLASMA WAVES IN SEMICONDUCTORS

Chapter I. Theoretical foundations of the existence of surface electromagnetic waves

1.1. Structure of the electromagnetic field near the surface of a magnetized semiconductor

1.2. Slow surface wave theory

Chapter II. Experimental method

2.1. Requirements for the experimental method

2.2. General principles of the technique

2.3. Experimental setup

2.4. About measurement technology

2.5. Sample Options

Chapter III. Traveling wave mode

3.1. Experiment idea

3.2. Wavefront Shape Study

3.3. Slow wave interference

3.4. Basic properties of the wave

3.5. Wave reflection from the edge of the waveguide plane

3.6. Surface wave excitation efficiency

3.7. Wave-surface connection

Chapter IV. Waveguide propagation of the PMV

4.1. The decisive experiment

4.2. Waveguide mode formation

4.3. Region of wave existence

4.4. Attenuation of slow surface waves

4.5. Effect of temperature on wave propagation

Chapter V. Standing wave regime

5.1. Wave motion pattern

5.2. Flat Fabry-Perot resonator

5.3. Surface wave dispersion

5.4. Wave field structure

5.5. Surface wave polarization

5.6. Helicon beams

Chapter VI. Devices based on slow PMVs

Part II. SURFACE ELECTROMAGNETIC WAVES ON SALT WATER

Chapter I. Analytical review

1.1. History of research

1.2. Analysis of negative research results

1.3. Criticism of the concept of L.I. Mandelintamma

1.4. A modern view of the Zenneck wave 1.5 Properties of the Zenneck wave

Chapter II. Experimental wave search

2.1. Experimental method

2.2. Observation of the Zenneck-Sommerfeld wave

2.3. Standing PEV on a flat water surface

2.4. Experiments with traveling waves

2.5. Radial divergence of surface wave

2.6. Vertical field structure

2.7. Emitter PEV Zenneka

Chapter III. Applications of Zenneka PEV

3.1. Laboratory experiments by location

3.2. On the excitation of SEW on the ocean surface

3.3. Hansen's natural experiment

3.4. About the methodology of a full-scale experiment

3.5. Marine radio communications

3.6. PEV radar

Conclusions to Part II. Why has the Zenneck wave not been observed under natural conditions?

MAIN RESULTS

Recommended list of dissertations

• Electromagnetic wave phenomena in confined and nonequilibrium solid-state electron plasma 1998, Doctor of Physical and Mathematical Sciences Popov, Vyacheslav Valentinovich

• Effects of resonant transformation of the polarization of electromagnetic waves in structures with two-dimensional electron magnetoactive plasma 2001, Candidate of Physical and Mathematical Sciences Teperik, Tatyana Valerievna

• Propagation and emission of electromagnetic waves in an open structure with two-dimensional electron plasma and a periodic metal lattice 1998, Candidate of Physical and Mathematical Sciences Polishchuk, Olga Vitalievna

• Wave processes and control of electromagnetic radiation in guiding structures with frequency and spatial dispersion 2010, Doctor of Physical and Mathematical Sciences Sannikov, Dmitry Germanovich

• Acoustic and spin waves in magnetic semiconductors, superconductors and layered structures 2009, Doctor of Physical and Mathematical Sciences Polzikova, Natalya Ivanovna

Introduction of the dissertation (part of the abstract) on the topic “New types of surface electromagnetic waves in conducting media”

In 1873, James Clerk Maxwell formulated the equations that bear his name and predicted the existence of electromagnetic waves that travel at the speed of light. Heinrich Hertz's classic experiments observed electromagnetic waves in free space. The results of these experiments quickly gained worldwide fame and recognition. The history of studies of surface electromagnetic waves arising at the interface between two media with different dielectric properties has not been so simple, truly dramatic.

The concept of “surface electromagnetic waves” (SEW) was introduced into science by Arnold Sommerfeld, when in 1899 he considered the problem of an axial current in a long straight wire and obtained solutions to Maxwell’s equations, the amplitude of which quickly decreases with distance from the surface of the wire. These solutions were interpreted by him as SEWs, perhaps by analogy with Rayleigh surface acoustic waves. Surface electromagnetic waves were apparently first observed experimentally by R. Wood in 1902 during the scattering of electrons in a thin metal foil. The phenomenon was not understood at the time and remained known as "Wood's anomalies" until the 1960s. Following A. Sommerfeld, German theorists Kohn and Uller established that a flat interface between a dielectric and a good conductor has a guiding effect on the propagation of a body wave and that SEW is possible at a flat interface with low losses.

In 1901, a historical event occurred: Guglielmo Marconi made a radio transmission across the Atlantic Ocean at a frequency of 30 kHz. This amazing discovery led to speculation about the mechanism of radio wave propagation. At that time, the existence of the Earth’s ionosphere was not yet suspected, so the possibility of long-distance radio communication due to the reflection of a radio beam from the ionosphere was not discussed. Instead, it was suggested that his experiments excited a new type of radio wave—a surface wave (SW).

Perhaps for this reason, Sommerfeld’s graduate student Jacek Zenneck began to clarify the issue in 1907. He pointed out the connection between the research of Kohn and Uller with the question of the propagation of radio waves over the earth's surface. In development of their results, J. Zenneck showed that in a medium not only with small, but also with large losses, Maxwell’s equations with the corresponding boundary conditions admit a solution that can be called a surface wave, directed by a flat interface between two media:

Hertz P-vector) 6 i.e. is a combination of two plane waves, one of which is localized in the air, the other in the medium. If the medium has finite conductivity, then a and P are complex. The dispersion relation for PVs propagating along the interface between media with dielectric constants 8 and e0 has the form k k,

2 &0 O where k and co are the wave vector and frequency of the wave; co - ?

CO C c - speed of light in vacuum. The wave is “tied” to the surface, its phase speed is slightly higher than the speed of light in a dielectric and depends on the properties of the underlying surface. Zenneck believed that the field of a real emitter at a great distance from it would have the appearance of the wave he found. However, from his work it follows only that the solutions of the above form are compatible with the equations of electrodynamics, the possibility of the existence of PV, but the field is in no way connected with the antenna, i.e. The main point of the radiation problem has not been revealed.

The first rigorous theory of the propagation of electromagnetic waves emitted by a dipole located on a flat interface between two homogeneous media (earth and air) was given by A. Sommerfeld in a classic work of 1909. A significant step forward made by him was that he did not consider the earth to be an ideal conductor, and the atmosphere to be an absolute insulator, and attributed to each half a certain finite dielectric constant and conductivity.

Sommerfeld showed that the electromagnetic field emitted by a dipole can be represented as the sum of a surface and volume wave. He believed that the SW predominates at large distances and thus he established the connection between the surface wave and the radiation source. In other words, he considered it proven that at long distances the field from a point source is a Zenneck PV. The concept of PV Tsennek, supported by the authority of Sommerfeld, was almost generally accepted for a long time. It was applied to the interpretation of many anomalous phenomena observed during the propagation of radio waves, for example to the so-called. "coastal refraction", when a wave traveling over the sea is reflected from the shore.

However, starting in 1919, in the theoretical works of Weyl, Van der Pol, V.A. Fock and others, this conclusion was challenged and found to be erroneous. A. Sommerfeld himself, recognizing the inaccuracies in the calculations, did not consider the concept of a surface wave to be erroneous. The dispute between theorists could only be resolved by experiment. Such an experiment was first carried out by Feldman in 1933, who studied the propagation of radio waves near the surface of the Earth (earth ray) and did not detect SW. Barrow then attempted in 1937 to detect the Zenneck surface wave by exciting radio waves over the surface of Lake Senneck in New York State and also failed. A series of large-scale experiments were carried out in our country under the leadership of academicians L.I. Mandelstam and N.D. Papaleksi. For a number of years, from 1934 to 1941, the radiation field of conventional radio antennas was studied, the propagation of radio waves along the earth's surface (over land and sea) was studied, but under no circumstances was a surface electromagnetic Zenneck wave observed. Since then, in Russian radiophysics, the opinion has been firmly established that it is impossible to excite this wave with real emitters, and that the very concept of a Zenneck surface wave does not correspond to physical reality.

A paradoxical situation has arisen: the existence of a surface electromagnetic wave follows from Maxwell’s equations, but it is not observed experimentally. Thus, the validity of the electrodynamics equations was called into question. The desire to resolve the paradox forced the author to set the task of conducting independent research in laboratory conditions. The result obtained confirms the correctness of Sommerfeld and Zenneck and eliminates the contradiction.

As a result of the events described, interest in surface electromagnetic waves dropped greatly, and in the 40-50s they were practically not studied. A revival of interest in SEW occurred in the 60s in connection with the study of the interaction of radiation with matter, mainly with solids and plasma. Stern and Ferrell were apparently the first to show that the peaks observed in the low-energy region during inelastic scattering of fast electrons in a metal foil (Wood's anomaly) can be explained by the excitation of surface plasmons at the interface between the metal and the oxide film covering it. Powell's experiments confirmed the theory's predictions. The surface plasmon is described by the upper part of the SEW dispersion curve, located near the plasma frequency. (curve 4 in Fig. 2)

In recent years, surface electromagnetic waves have been studied theoretically and observed experimentally in various laboratories around the world. At the same time, two significant conclusions were made. First, a clear definition of a surface wave was given: it is a wave that decays exponentially as it moves away from the surface along which it propagates. The wave field distribution is the best evidence of its surface nature. Secondly, it is shown that a surface wave can be considered a characteristic type of vibration for a given surface. Excitation of the PV is an independent problem and should not be confused with the conditions for the existence of the wave. Since the phase velocity of the SEW is somewhat different from the speed of light in air, it can be excited using a body wave only if the condition of synchronism is met—approximate equality of phase velocities, or more precisely, equality of the components of wave vectors in the direction of propagation. It follows from this that not every emitter can excite a surface wave. According to modern theoretical concepts, two cases are possible (Fig. 1 from the work)

Regions of existence of Fano and Zenneck SEVs

Tsennek 8 p o

1) e-complex quantity,0. Then on the interface there are so-called Fano waves with phase velocity V< с (прямая 5 на рис2), наблюдающиеся в газоразрядной плазме (поверхностные плазмоны), в полупроводниках и металлах. В настоящее время они активно исследуются и применяются в спектроскопии поверхности .

2) z-complex quantity, c" > -8o, c" > 0, . A surface Zenneck wave with phase velocity V > c appears at the flat interface (straight line 6 in Fig. 2). This wave had not been observed before our work. The interface (curve 1 in Fig. 1) between the regions of existence of Fano and Zenneck is determined by the equation s

0 e0 where 8=8" + 18"

When passing from a flat interface to a curved one with a small radius of curvature, less than the wavelength, the Zenneck wave transforms into a Sommerfeld wave. The latter is described by another, more complex dispersion equation, including the cylindrical Bessel and Hankel functions. A group of researchers managed to excite a Zenneck-Sommerfeld SEW wave in the microwave range in laboratory conditions, prove its superficial nature and measure its main characteristics.

A new stage in the study of SEW in gas and solid-state plasmas is associated with taking into account the influence of an external magnetic field on the conducting medium. In a magnetic field, the conducting medium becomes gyrotropic, a new characteristic appears—the frequency of cyclotron rotation of carriers, which leads to a change in the properties of known SEMs (Fig. 2). Surface plasmon (curve 4 in Fig. 2), for example, is transformed into magnetoplasmon with a slightly lower (several %) phase velocity. It was believed, however, that the influence of the magnetic field was not very significant.

The author experimentally established (together with V.I. Baibakov) that in a constant magnetic field the electrodynamic properties of the surface of a conducting medium change dramatically. This leads to the emergence of a fundamentally new class of surface electromagnetic waves (curve 1 in Fig. 2). They exist only on the surface of magnetized plasma, have unique properties and propagate with phase velocities much lower than the speed of light in vacuum, for which we called them slow surface magnetoplasma waves (SMWs). Sometimes in the literature they are called surface helicons or Baibakov-Datsko waves

Spectrum of surface electromagnetic excitations 1-slow PMV; 2-light in dielectric; 3-Langmuir waves - volumetric plasmons; 4-surface plasmons in plasma (polarites in dielectrics, magnons in magnets); 5-fano wave; 6-Zenneck wave;

The dissertation consists of two parts. The first part is devoted to slow surface magnetoplasma waves in semiconductors, the second part is devoted to surface electromagnetic waves in salt water. We discovered slow PMVs in solids in 1971. During their

After ten years of study, a technique was developed for excitation, separation from the mixed field, identification and measurement of the main characteristics of surface electromagnetic waves in laboratory conditions. This made it possible in subsequent years to experimentally prove the existence of a surface electromagnetic Sommerfeld-Zenneck wave.

Slow PMV in 1p8b

The theory of slow PMVs in semiconductor plasmas was constructed after their experimental discovery. The existence and properties of slow surface magnetoplasma waves follow from the solutions of Maxwell's equations written for a limited conducting medium with appropriate boundary conditions and are described by a fourth-order dispersion equation. The theory of the phenomenon was built by a group of Kharkov theorists under the leadership of V.M. Yakovenko. Its main provisions are as follows.

In a constant magnetic field, the electromagnetic properties of a semiconductor are anisotropic. If the magnetic field vector H is directed along the Ob axis, then the dielectric constant of the medium is described by the gyrotropic tensor 0

XX xy 0 xy yy

0 0 where the off-diagonal components correspond to the high-frequency Hall current.

In a semiconductor in a constant magnetic field, there are two bulk electromagnetic waves (ordinary-anti-helicon and extra-ordinary-helicon, characterized by the opposite direction of circular polarization) with different propagation characteristics. At frequencies much lower than the collision frequency of carriers V, as well as plasma Jp and cyclotron coc. (with « Shp, coc, V) under the condition V « coc, extraordinary waves have slight attenuation, and the semiconductor turns out to be a transparent medium for them with a large effective refractive index. However, none of these waves can be surface, since they do not satisfy the boundary conditions on the surface of the semiconductor, which consist in the continuity of the components of the wave’s magnetic field strength vector at the interface. These conditions are satisfied for the superposition of ordinary and extraordinary waves that make up surface magnetoplasma waves at the interface

11 of two types: fast (y ~ c), which in the absence of an external magnetic field transform into known surface electromagnetic waves (surface plasmons) and slow (y ~ c) PMVs, which do not exist without a magnetic field.

Let the semiconductor occupy the half-space<0 и граничит с вакуумом. Тогда, при условиях у « С0С; С22| » |8ху| » |£хх|:

8 XX £ 22 xy the dispersion and the region of existence of slow waves are determined by the relations

2 2 С SOZ in [£уу (1 + БШ 2 в) + 218ух БШ in

After simplification (2) takes the form с = к2Нпс 2 ме

Ya0.ush@< О где 3 = а затухание:

A co (ku ~ k*)exhu co y L, 2 yy

5) the angle between the magnetic field H 0 and the two-dimensional wave vector k in the plane of separation of the media, X2~component of the wave vector in the medium, co-frequency, c-speed of light in vacuum, n-concentration of the main charge carriers in the semiconductor, e-electron charge .

Relation (2a) shows that slow PMVs have a quadratic dispersion law, relation (3) shows that wave propagation along the magnetic field is impossible, i.e. the waves are oblique and exist only in two narrow sectors. Relationship (4) means that the waves are non-reciprocal (unidirectional) with respect to the direction

12 constant magnetic field. Slow surface magnetoplasma waves can exist in the following media:

1) in a single-component semiconductor with a relatively low carrier concentration, when the bias current is greater than the conduction current;

2) in a dense (the bias current is small) single-component solid-state plasma with an anisotropic mass of carriers; a similar thing is observed, for example, in multi-valley semiconductors;

3) in a dense single-component plasma with magnetized electrons and unmagnetized holes.

A diagram of the region of existence of slow PMVs in a specific semiconductor, indium antimonide, is shown in Fig. 3. X

Fig.3. Theoretical region of existence of slow surface waves in indium antimonide (top view of the semiconductor surface). e1 = 45°-60°, e2 = 135°-150°. The curly arrow indicates the direction of the magnetic field

We experimentally discovered slow PMVs and studied them in indium antimonide, a semiconductor with high carrier mobility (up to l

77000 cm /V.sec at T=ZOOK), mainly at room temperatures, in the frequency range 10 MHz - 2 GHz and in magnetic fields up to 30 kOe. The experimental method developed by the author made it possible to excite and receive slow waves and study their properties in various propagation modes:

Standing wave (flat Fabry-Perot resonator);

Waveguide;

A traveling plane wave on a free surface.

It was in this sequence that the experiment proceeded over time. Each of these modes made it possible to determine those characteristics of the wave that could not be obtained by other methods, reproducing

13 believed and complemented others. Experimental evidence of the existence of a new class of surface electromagnetic waves boils down to the following established facts.

Region of existence.

Figure 8 shows a diagram of one of the experiments in which waves traveling along a free surface were observed. The dependence of the power of the RF signal passing along the surface of the semiconductor on the orientation of the magnetic field is shown in Fig. 20. It can be seen that on the surface of a magnetized semiconductor there are two selected directions in which the greatest signal transmission is observed. These directions coincide with the sectors of the theoretical area of ​​existence of slow PMVs.

Slowness of the wave.

The type of wave traveling along the surface in a given selected direction, at a certain angle to the magnetic field, was recorded (Fig. 18). Comparison of its length X with the length of an electromagnetic wave of the same frequency in vacuum X0 shows that 103 I i.e. X « X0 and the wave is slow.

Dispersion

By measuring the dependence of the wavelength on the frequency and magnetic field strength, it was established that its dispersion is quadratic and coincides with the theoretical one, determined by relation (2); the dispersion curve is shown in Fig. 43. The dispersion depends on the magnitude of the magnetic field, i.e. the wave is magnetoplasma.

Non-reciprocity

Numerous experiments have established that slow waves have unidirectional propagation, which is confirmed, in particular, by Figs. 17, 20. Unidirectional propagation was also observed in the mode of their waveguide propagation (Fig. 31). Waveguide modes are formed when the surface of the semiconductor is limited by parallel edges normal to the magnetic field. In this case, the wave propagates across the field.

Surface connection

The directions of wave propagation are uniquely determined not only by the orientation of the external magnetic field, but also by the orientation of the normal to the surface of the semiconductor. This effect of “attachment to the surface” is clearly manifested when a wave is excited on the planes of an indium antimonide plate magnetized parallel to its plane. The experimentally recorded diagram of the directions of wave propagation on the planes of the plate is shown in Fig. 28. Waves excited on the upper and lower planes in accordance with the orientation of the normals to these planes run in opposite directions towards each other.

Transverse structure of the wave field

The field distribution is shown in Fig. 44. It can be seen that the field of the surface wave decreases on both sides of the semiconductor surface, but its maximum is not on the surface, but is shifted deep into the medium. Such an amplitude distribution is unusual for surface waves and is not observed for other waves of this type (fast surface electromagnetic waves, gravitational-capillary waves on the surface of a liquid, surface acoustic waves). The shift of the wave field maximum below the surface of the semiconductor is caused by the peculiarities of the propagation of electromagnetic waves in a gyrotropic medium and is explained by the interference of two partial waves that exist in the bulk of the semiconductor (ordinary and extraordinary) and have different rates of field decay deep into the semiconductor, and are in antiphase on its surface.

Attenuation

For intrinsic indium antimonide at room temperature and in a magnetic field of 18 kOe, the attenuation is 2.7 dB or 1.35 times the amplitude per wavelength. Under the same conditions, the wavelength in the direction of the magnetic field is ~7 mm (in the direction of propagation X-5 mm), so the attenuation per unit length is approximately 0.4 dB/mm or twice the amplitude at a distance of 10 mm. For a slow PMV, the attenuation per wavelength is constant and does not depend on frequency.

Polarization

The maximum signal transmission along the surface of the sample (Fig. 46) is observed when a radiator is installed that excites the TE wave (the H-component of the field is normal to the surface), which corresponds to the PMV theory. Strictly speaking, the wave is elliptically polarized.

The scientific and practical significance of the results obtained lies in the fact that the spectrum of known surface electromagnetic oscillations of the optical frequency range (plasmons, polaritons, magnons) is supplemented by two new branches: a slow surface magnetoplasma wave and a fast Sommerfeld-Zenneck wave, discovered in HF and Microwave range, which opens a new HF direction of research in surface electrodynamics.

Based on slow PMVs, new methods for studying the surface of conducting media (metals, semiconductors, plasma), methods for determining the parameters of semiconductors, diagnostics of solid-state plasma, as well as new types of magnetic field sensors, radio engineering devices for various purposes, active solid-state microwave devices and magnetoplasma TWTs can be created. , controlled elements of planar optical information processing systems.

The significance of the research extends beyond solid state physics. Favorable conditions for the propagation of slow magnetoplasma waves exist in the Earth's ionosphere. If they are experimentally discovered, it is possible to use PMVs for research and active influence on the Earth’s ionosphere, as well as for creating additional radio communication channels.

A priority

Any new physical phenomenon must be discussed and recognized by the scientific community, therefore it is appropriate to provide information about its priority and recognition in Russia and abroad.

The possibility of the existence of slow PMVs was theoretically substantiated in the article by S.I. Khankina and V.M. Yakovenko “On the excitation of surface electromagnetic waves in semiconductors,” which was received by the editors of the journal “Solid State Physics” on July 19, 1966. . The experimental detection of slow waves was reported by V.I. Baibakov and V.N. Datsko in the priority article “Surface waves in ln8b”, received by the editors of the journal “JETP Letters” on January 17, 1972.

After we published our main works, articles appeared that touched on the priority and significance of the new phenomenon. For example, Fly and Queen's paper noted that "Baibakov and Datsko presented experimental results indicating that a new low-frequency surface wave exists in the room-temperature electron-hole plasma of HnSb"; A.B. Davydov and V.A. Zakharov point to the priority of S.I. Khankina and V.M. Yakovenko in theoretical research, and V.I. Baibakova and V.N. Datsko in experimental research of a new type of surface waves. In the article by E.A. Kaner and V.M. Yakovenko in the journal "Advances in Physical Sciences" it is noted that the surface helicon wave, predicted

16 involved in the work was recently discovered experimentally by Baibakov and Datsko in indium antimonide."

The question of the reliability of the discovered phenomenon was widely discussed in the scientific literature; in the discussion the authenticity was proven. Independent experimental confirmation was the work of G. Ruybis and R. Tolutis.

Surface electromagnetic waves on salt water

Any real source of electromagnetic field located at the interface between two media excites both surface and volume waves; separating them turns out to be a difficult experimental task. In our experiments, SEWs were observed in laboratory conditions on the surface of water of varying salinity (mainly 35%o) in the frequency range 0.7-6.0 GHz. Previously developed methods for exciting and studying standing and traveling surface waves were used.

In the standing wave mode, the Sommerfeld-Zenneck wave (a cylindrical modification of a flat Zenneck PV) was first observed on a column of salt water placed between two metal sheets representing a flat Fabry-Perot resonator. The dispersion and transverse distribution of the field were measured, clearly indicating its surface nature. A surface electromagnetic wave was also studied on a flat surface of water in a resonator of two flat parallel plates immersed in water under conditions of its dimensional resonance. At the same time, the PV was separated from volumetric fields and its amplitude structure was measured.

In the traveling wave mode, using a specially designed emitter, it was possible to tear off volumetric radiation from the surface and direct it upward at a large angle to the horizon, thereby freeing the PV from the admixture of the volumetric field. In the radiation of such a source located above the surface of the water, the presence of a wave propagating along the surface is detected, the amplitude of which decreases with the distance p to the emitter, which corresponds to the divergence of the PV excited by an axially symmetric source. Measurements of the vertical structure of the field in this wave showed that the field decreases exponentially with distance from the surface, and the measured dependences of the localization height on frequency and water salinity turned out to be in good agreement with theoretical calculations.

An analysis of the results of the only experiment known to us (Hansen, USA, 1974) on the propagation of an electromagnetic field in the decameter range (5-30 MHz), excited by special antennas, over the ocean surface along a path length of 237 km was carried out. Unlike Hansen, who found an inexplicable anomaly in the propagation of the electromagnetic field, we concluded that in his experiment a mixture of volume and surface waves was excited, and the path itself selected less damped waves. We have shown that at frequencies below a certain salinity-dependent critical frequency (15 MHz in the case of Hansen), the Zenneck PV is attenuated much less than the ground beam. Consequently, at a frequency above 15 MHz, the propagation of the electromagnetic field occurred in the form of a ground beam, and at a frequency below 15 MHz, in the form of a Zenneck PV, which explains the anomaly. The relative SW attenuation data obtained from Hansen's work is in good agreement with the results of our own laboratory measurements.

Observing and identifying the Zenneck wave in the laboratory is the first step in studying this phenomenon. The next step is to study it in natural conditions. We have considered various aspects of the propagation of SW over the ocean surface (curvature of the Earth, the influence of waves) from the point of view of the possibility of creating new long-range radio communication channels and a Zenneck surface wave radar.

The dissertation material is presented in the following sequence.

Part I. Slow PMVs in semiconductors

Chapter I examines the spectrum of normal electromagnetic waves on the surface of a magnetized semiconductor and outlines the theory of a slow surface magnetoplasma wave.

Chapter II describes the experimental technique, experimental setup, and the parameters of the samples.

In Chapter III, waves traveling along a free surface were studied, the region of their existence was found, the shape of the wave, the nonreciprocity of propagation and the dependence of the length on the angle between the direction of its propagation and the orientation of the magnetic field were established, the surface wave and the subsurface helicon were separated.

Chapter IV is devoted to surface waves in limited structures (waveguide propagation mode). The region of existence of a wave in a magnetic field was established, the attenuation and influence of temperature on the propagation characteristics were measured, and the pronounced nonreciprocity and unidirectionality of wave propagation relative to a magnetic field was demonstrated.

Chapter V presents the results of a study in the standing wave mode in a Fabry-Perot surface resonator. The pattern of wave motion is considered, its structure, dispersion and speed are determined. The effect of an unusual concentration of the volume wave field, the formation of helicon beams in the volume of a semiconductor, discovered during the study of slow PMFs, is described.

In Chapter VI, 12 radio engineering devices are proposed that could be created on the basis of slow surface magnetoplasma waves.

Part II Surface electromagnetic waves on salt water

Chapter I provides an analysis of work on surface electromagnetic waves without a magnetic field: the fundamentally important points of A. Sommerfeld’s theory are given; the theoretical concept of L.I. Mandelyptamma is critically reviewed; a modern view of surface electromagnetic waves is presented; The basic properties of the Zenneck wave are described.

Similar dissertations in the specialty "Radiophysics", 04/01/03 code VAK

• Electromagnetic excitations in conductors with an anisotropic band structure 1984, candidate of physical and mathematical sciences Savinsky, Sergey Stepanovich

• Regularities of formation of ordered micro- and nanostructures in condensed matter under laser excitation of surface polariton modes 1999, Doctor of Physical and Mathematical Sciences Soloviev, Oleg Viktorovich

Conclusion of the dissertation on the topic “Radiophysics”, Datsko, Vladimir Nikolaevich

MAIN RESULTS

1 It has been proven that slow (s) surface electromagnetic waves exist in a magnetic field at the interface between a plasma-like medium and a dielectric.

2 The spectrum of surface electromagnetic oscillations is supplemented by a low-frequency branch: slow magnetoplasma waves were discovered and studied in indium antimonide at 200-400 K, in the HF and microwave ranges and in magnetic fields up to 30 kOe. The domain of existence is established; dispersion; phase velocity and attenuation, transverse field structure; polarization.

3 It has been established that in a magnetized semiconductor, the bulk helicon near the surface is transformed into a pseudosurface wave.

4 An experimental method has been developed for studying surface slow magnetoplasma and fast electromagnetic waves on the surface of conducting media.

5 The phenomenon of “electromagnetic puncture” was discovered: in an indium antimonide plate placed in a magnetic field normal to its plane, the microwave electromagnetic field, with inhomogeneous excitation, propagates throughout the volume in the form of a wave with an anomalously concentrated field, different from the known helicon.

7 12 devices based on slow surface magnetoplasma waves have been proposed, and two certificates of authorship have been obtained.

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