Faculty of Physics
M.V.Lomonosov Moscow State University

## Rayleigh gas with sources of heavy particles

Moscow University Physics Bulletin 1982. 37. N 2. P. 1

Based on a solution of the Fokker-Planck equation, the distribution function of the translational energy is solved for a Rayleigh gas with sources of heavy particles. The nature of disturbances in the equilibrium distribution function caused by the source of the particles is analyzed.

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## Properties of the loci of roots of the class of self-regulating systems containing a network element described by the heat conduction equation

### G.A. Bendrikow, L.D. Lozinskii

Moscow University Physics Bulletin 1982. 37. N 2. P. 6

The article presents a generalization of the root locus method to the class of linear self-regulating systems containing not only elements described by ordinary differential equations with constant coefficients, but also an element described by a one - dimensional heat conduction equation.

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### G.A. Сhуzhоv, O.F. Dorofeev

Moscow University Physics Bulletin 1982. 37. N 2. P. 12

Coherent - oscillator radiation is considered. A comparison is made with the radiation of a classical particle, and an estimate is given for the decay probability of the coherent state in the process of spontaneous emission.

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## Mechanism of strontium- and barium-ion formation in a discharge in a cooled hollow cathode

### L.M. Vоlкоva, A.M. Devуatоv, V.Kh. Fazlaev

Moscow University Physics Bulletin 1982. 37. N 2. P. 17

The formation of Sr$^+$ and Ва$^+$ ions in a cooled hollow cathode in a discharge filled with argon and helium is investigated. The concentration of Sr$^+$ and Ва$^+$ ions is determined from the measured absorption coefficients of their resonance lines and also from the solution of the balance equation.

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## Solving the chain of Bogolyubov equations for a crystal

### I.P. Bazarov, P.N. Nikolaev

Moscow University Physics Bulletin 1982. 37. N 2. P. 22

On the basis of expansion in powers of a small parameter, the chain of Bogolyubov equations for the crystal state is solved. Ah expression is obtained for the s-particle distribution function up to second order, inclusive.

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## Determining the concentration of free charge carriers in PbTe and Pb$_{0,8}$ Sn$_{0,2}$Te from the reflection spectrum in the far-ir region

### A.G. Вelоv, E.P. Rashevskауa

Moscow University Physics Bulletin 1982. 37. N 2. P. 27

A contactless nondestructive method of determining the concentration of free charge carriers in PbTe and Pb$_{0,8}$ Sn$_{0,2}$Te from the IR reflection spectrum in the wavelength range 20-120 microns is proposed. Theoretical calibration curves are constructed, allowing the charge-carrier concentration in PbTe at T = 300 and 80 К and in Pb$_{0,8}$ Sn$_{0,2}$Te at T = 80К to be determined from the position of the point of inflection of the spectral dependence of the reflection coefficient on the light wavelength. The error of the metod is estimated, and shown to be no more than ±30%.

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## Nonconservation of spatial parity in neutrino magnetobremsstrahlung

### V.M. Zakhartsov

Moscow University Physics Bulletin 1982. 37. N 2. P. 32

The angular distribution of neutrino pairs emitted by a relativistic electron moving in a magnetic field is considered. It is shown that the particles are emitted predominantly in the opposite direction to the magnetic field. This asymmetry directly reflects the nonconservation of spatial parity in the given process. On account of radiation reactive forces, the electron is accelerated in the direction of the magnetic field. Expressions are obtained for the asymmetry parameter of the radiation and the radiation reactive force, depending both on the magnetic field strength and the electron energy and on its polarization.

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## Structure of disconnection shock waves in plasma

### A.V. Danilov

Moscow University Physics Bulletin 1982. 37. N 2. P. 36

The structure of the front of disconnection shock waves in completely ionized plasma is investigated. In the case of nonmagnetized plasma, the shock wavefront at M$_1$>1 consists of a narrow isomagnetic discountinuity, followed by a broad (of the order of the magnetic - field diffusion length) region of Joule dissipation, in which the transverse component of the magnetic field declines from the initial value to zero. At sufficiently large values β=8πnT/ H$^{2}$≫1 the width of the shock wave front is determined again by the scale characteristic of electronic thermal conductivity. For magnetized plasma, the width of the front is of the order of. the characteristic length of electronic thermal conductivity. When M $^{2}$ $_1$ > 4/5, M$^{2}$ $_2$>4/5 an internal ionic shock wave arises in the structure of the front.

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## Mechanism of formation of cumulative π$^{-}$ - mesons in the interaction of high-energy deuterons with protons protons

### A.M. Popova, S.G. Serebryakov, E.K. Shabalina

Moscow University Physics Bulletin 1982. 37. N 2. P. 42

A theoretical description is proposed for the process d+p→ π$^({-})$ (0°)$^{+}$ with a primary - deuteron momentum of around 10 GeV/c, allowing both qualitative and quantitative accounts of the cumulative creation of π$^{-}$ mesons to be given. This model is developed on the basis of representation of the given process as a three – particle problem, taking account of two- and three - particle forces. The amplitude of the reaction is represented as a sum of contributions from an infinite series of diagrams, including the peaks of the two- and three-particle interactions. It is shown that, at high energy, the simplest diagrams make an important contribution to the amplitude of the cumulative meson formation. The differential cross section calculated for the formation of π$^{-}$ mesons at 0 in the reaction (d + p) is in good quantitative agreement with experimental data.

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## Dispersion relations for the refractive indices of normal waves

### V.V. Кrуlоv

Moscow University Physics Bulletin 1982. 37. N 2. P. 48

The analytical properties of the refractive indices of normal waves are considered, for the example of normal waves in laminar media and surface waves. It is shown that the possibility of wave transmission through the layer is characterized by the appearance of branching points in functions of the refractive index not lying on the real frequency axis and violating the condition of applicability of dispersion relations of Kramers - Kronig type to normal waves. In the case of surface waves, analogous disruption of analyticity characterizes the possibility of the emission of surface-wave energy into the volume of the medium.

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## Basic apparatus parameters of cylindrical electrostatic analyzers for investigating magnetospheriс plasma

### Т.В. Bondareva, V.I. Lazarev

Moscow University Physics Bulletin 1982. 37. N 2. P. 52

On the basis of athree - dimensional representation of the transmission function of an electrostatic analyzer with cylindrical plates, a method of practical calculation of the basic parameters of an analyzer with a slit diaphragm at the inlet is developed. The characteristics of an analyzer with specified properties are calculated. The characteristics obtained are in good agreement with the results of experimental verification.

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## Hydrological processes in the coastal region of the sea

### N.К. Shelкоvniкоv, V.V. Timоfееv

Moscow University Physics Bulletin 1982. 37. N 2. P. 59

Full - scale investigations are performed in the coastal region of the sea. As a result of analyzing the spectra of temperature, flow, velocity, and components of the wind velocity,oscillations at a frequency of 0.40 cycle/hr due to internal waves are discovered.It is suggested that wind is the energy source.

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## Model of the oxygenic conditions of a fresh-water basin with summer heating, taking account of the settling of organic material

### V.V. Alexееv, Yu.I. Gorbatov, A.O. Kokorin

Moscow University Physics Bulletin 1982. 37. N 2. P. 65

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