Faculty of Physics
M.V.Lomonosov Moscow State University

## The tetrad techпique in the theory of relativistfc plasma waves with radiative frictioп

### L.S. Кuz'mепkоv, N.D. Nаumоv

Moscow University Physics Bulletin 1979. 34. N 3. P. 1

We develop a covariant method of calculating the oscillations in a relativistic plasma with radiative damping on the basis of the tetrad formalism. The resulting Lorentz-invariant dispersion relation is examined for the cases of transverse, Langmuir, and ion-sound oscillations in a plasma whose unperturbed state is described by a relativistic Maxwellian distribution. The relation between the radiative damping time and the Landau damping time is analyzed.

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## Kпеtiс equation for localized electrons in the field of а strong electromagnetic wave

### I.Р. Zvуаgin

Moscow University Physics Bulletin 1979. 34. N 3. P. 7

We obtain a kinetic equation describing the low-frequency relaxation function of the occupation of localized states in the presence of both a constant electric field and a strong electromagnetic wave. By investigating the solutions of this equation using the ideas of flow theory, one can find the effect of a strong electromagnetic wave on the hopping conductivity in two cases: a) when the conductivity is due to hops along a narrow band of impurity centers which are randomly distributed in space, and b) when the energies of the localized states are continuously distributed over a wide interval. It is shown that in the first case the weakening of the effective electron-phonon interaction in the field of the wave leads to a negative photoconductivity, and in the second case there must be a specific exponential dependence of the hopping conductivity on the amplitude of the wave.

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## On the problem of interband optical absorption in disordered semiconductors

### V.L. Воnсh-Bruеviсh, V.D. Iskrа

Moscow University Physics Bulletin 1979. 34. N 3. P. 16

We calculate the absorption coefficient of light in a disordered semiconductor for photon energies smaller than the width of the forbidden band. The interaction of the electrons both with the random field which produces the spectrum of fluctuational levels and with phonons(the multiphonon radiator transitions) is considered.

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## А method of solviпg of f our particles proЫem iп quaпtum mechaпics

### I.Yu. Коvаlуоvа, V.V. Коmаrоv, А.М. Ророvа, V.L. Shаblоv

Moscow University Physics Bulletin 1979. 34. N 3. P. 25

In an approach to the study of many-particle systems based on the application of the formalism of second quantization and using the interaction representation, we obtain a system of equations for the amplitudes of the scattering of channels of four particles of finite mass in the case where the Hamiltonian of the system is assumed to include both pairwise and many-particle interaction potentials. We write in explicit form the corresponding integral equations for the channel amp litudes, which in this approach have a clear physical meaning and are directly connected with the channel Hamiltonians of the system.

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## Computatioп of ESR spectrum of iron ions in crystalline lattices (1)

### А.N. Теrеntjеvskу, V.N. Lаzukin

Moscow University Physics Bulletin 1979. 34. N 3. P. 33

We examine the spin-Hamiltonian formalism for paramagnetic systems of ions of the iron group. We obtain more exact analytical expressions for the angular dependence of the fine EPR spectra for different symm etries. The theoretical results are displayed graphically for a number of systems.

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## Оп deep nonelastic asymptotic Feinman's diagrams with crossed lines

### N.I. Usуukinа

Moscow University Physics Bulletin 1979. 34. N 3. P. 43

We discuss the deep inelastic asymptotic behavior of the series of nonplanar Feynman diagrams with crossing lines in the t channel in $λφ^{3}$ theory. In this treatment we use the technique of a coordinate representation in which the deep inelastic asymptotic form is compared with that of the corresponding diagrams on the light cone. The examination is carried out in the region of small values of the scaling variable l/ω = $-k^2/2kp$.

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## The ring cyclotron as a kaon-neutron generator

### L.А. Sаrkisуаn

Moscow University Physics Bulletin 1979. 34. N 3. P. 49

We examine the status of the existing π-meson facilities and their prospects for development. We discuss the designs of K-meson and neutron facilities. Oh the basis of numerical modeling of the dynamics of the proton with the complete equations of motion on a computer, we establish the slow passage of the integral resonance with respect to the radial betatron oscillations $Q_{R}= 2(~845) MeV in an isochronous ring cyclotron, with the subsequent acceleration to$Q_{R} = 2.3(~1200 MeV). We detect the previously unknown phenomenon of strong postresonance(as opposed to the known adiabatic) damping of the amplitudes of the free radial oscillations of the charged particles perturbed in traversing the integral resonance as the radius of the orbit increases. This damping is due to the drift of the frequency of the radial oscillations from the resonance in the spatially varying magnetic field. The parameters of the ring cyclotron as a generator of kaons and neutrons are given for a proton energy of ~4.2 GeV.

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## То the space-time structure of the seasoпal thermocliпe

### N.К. Shelkovnikov, V.V. Timofeev, G.I. Alyavdin, S.I. Zaitzev

Moscow University Physics Bulletin 1979. 34. N 3. P. 57

We have carried out full-scale investigations in the littoral zone of the sea. The vertical profiles of the temperature, electrical conductivity, and current velocity have been obtained. We have also measured wind speeds, air temperatures, and the aggregate flux of solar radiation. Strong fluctuations were detected in the seasonal thermocline in the littoral zone. We have estimated the effect of turbulent heat exchange on the motion of the thermocline. It is shown that wind transfer plays the predominant role in changing the thermal regime of the littoral zone.

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## Generation of vind waves оп assisting current for short for etches

### G.Е. Коnоnkоvа, А.А. Рivоvаrоv, К.V. Роkаzееv

Moscow University Physics Bulletin 1979. 34. N 3. P. 63

We analyze the data of a laboratory experiment on the generation of wind waves for short fetches with and without a leeward current. In the case with the leeward current, the rate of growth of the spectral components decreases; we propose a mechanism explaining this phenomenon. A change in the shape of the spectrum is observed: the spectrum of the waves is shifted to higher frequencies, and the high-frequency branch becomes flatter. For short fetches the shape of the spectrum In the equilibrium interval depends on the dynamical velocity of the air flow. A decrease in the spectral density occurs more intensely than according to Phillips' law. In the initial stage of development of the wave disturbance a breakdown of self-modeling occurs.

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## Self-coпsisteпt optical potential of $^{12}$С пucleus

### F.А. Ghivорistsеv, Е.S. Rjеvsсkу

Moscow University Physics Bulletin 1979. 34. N 3. P. 70

Using a microscopic approach, we modify the optical model of nucleonnucleus scattering in the region of the inelastic threshold of light nuclei. Over a wide interval of energy averaging, the excitation of a single-particle resonance is treated as absorption and taken into account in the imaginary part of the optical potential. A self-consistent procedure is used in the calculations.

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## Оп the influence of radiation effects оп the beam instabllity

### L.S. Кuz'mеnkоv, Р.А. Роlуаkоv

Moscow University Physics Bulletin 1979. 34. N 3. P. 74

We examine radiative effects on the beam instability. It is shown that in contrast to the known results of beam-instability theory, taking the radiative friction of the electrons into account leads to the new result of an instability of the short-wavelength plasma oscillations ($ω_{p}<kV$). We obtain the radiative-friction corrections to the dispersion relations of waves whose phase velocity exceeds the thermal velocity of the electrons of the plasma and beam.

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## Оп the design of ап experimeпt aimiпg at the search of а local aпisotropy of space апd time

### G.Yu. Воgоslоvskу, V.I. Раnоv

Moscow University Physics Bulletin 1979. 34. N 3. P. 78

We propose an experiment which could detect local anisotropy of space and time. The expected effect is the frequency modulation of harmonic oscillations arriving at a receiver which is rotating at a constant speed around the source, the depth of modulation being proportional to the size of the anisotropy.

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## Variable-topology hodel in field theory

### D.D. Ivаnenko, G.А. Sаrdаnashvilу

Moscow University Physics Bulletin 1979. 34. N 3. P. 81

We investigate the possibility of using the topological-algebraic characteristics of field systems as their physical characteristics, of describing field systems immediately in terms of these characteristics, and of constructing a version of dynamics on the basis of these characteristics.

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## Production of particles with large transverse momenta in quantum chromodynamics

### V.V. Веlоkurоv

Moscow University Physics Bulletin 1979. 34. N 3. P. 85

It is shown that the assumption that the nonleading terms in the perturbation series cause a certain modification of the result of the leading approximation allows one to consider quark-quark scattering at a large angle to be one of the possible mechanisms for the production of hadrons with large $p_{⊥}$.

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## Оп evolution of intensive acoustic pulses with finite Reinolds numbers

### О.А. Vasiliеvа, А.А. Каrаbutоv, Е.А. Lарshin, G.Р. Раnаsеnkо, О.V. Rudеnkо

Moscow University Physics Bulletin 1979. 34. N 3. P. 89

We propose a numerical method of integrating Buger's equation which is free from limitations on the value of acoustic Reynolds number. We calculate the shape of unipolar and bipolar pulses in various cross section of the nonlinear medium. We construct the functional dependence of the peak value of the perturbation on the distance, on the basis of which we propose a new scheme for determining the nonlinear moduli in pulse measurements.

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## The excitation of Sr atoms iп hollow cathode discharge

### V.Ch. Fаzlаеv, А.М. Dеvуаtоv, S.V. Маkаrусhеv

Moscow University Physics Bulletin 1979. 34. N 3. P. 94

We present the results of measurements of the concentration of strontium atoms in the ground and excited states and the concentration and energy distribution function of the electrons in a hollow-cathode discharge; the filler gas was Ar at 20 Pa.

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## The Comptoп effect in а two-dimeпsioпal approximation of quaпtum electrodyпamics

### Yu.М. Lоskutоv, V.V. SkоЬеlеv

Moscow University Physics Bulletin 1979. 34. N 3. P. 97

In this paper we obtain the general form of the cross section for photon scattering by electrons in a strong magnetic field. We find the total scattering cross section in the nonrelativistic limit. It is shown that the scattered radiation is linearly polarized. Quantitative estimates are given, according to which it is hoped that the results can be checked experimentally.

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## Specific heat of liquids from the correspoпdiпg states priпciple

### L.Р. Рhуliрроv

Moscow University Physics Bulletin 1979. 34. N 3. P. 101

It is shown by analysis of data in the literature that the excess molar heat capacity of normal (nonassociated) liquids on the saturation curve is described by a single function of the reduced temperature and the defining criterion of thermodynamic similarity. Formulas approximating this function are given for the isobaric and isochoric specific heat. We examine the use of these principles for evaluating the specific heat of liquids.

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