Analysis of macroparticle charge screening in a nonequilibrium plasma based on the kinetic collisional point sink model
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CAL, NONLINEAR, AND SOFT MATTER PHYSICS
Analysis of Macroparticle Charge Screening in a Nonequilibrium Plasma Based on the Kinetic Collisional Point Sink Model A. V. Filippova,*, A. G. Zagorodnyb, A. I. Momotc, A. F. Pal’a,d, and A. N. Starostina a State
Research Centers of Russian Federation Troitsk Institute for Innovation and Fusion Research, Troitsk, Moscow, 108840 Russia b Bogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine, Kyiv, 03680 Ukraine c Taras Shevchenko National University of Kyiv, Kyiv, 01601 Ukraine d Skobeltsyn Research Institute of Nuclear Physics, Moscow State University, Moscow, 119991 Russia *e-mail: [email protected] Received June 2, 2017
Abstract—The screening of macroparticles in a nonequilibrium plasma is considered on the basis of the Vlasov kinetic equations supplemented with the collisional term in the Bhatnagar–Gross–Krook approximation and the point sink method. In this method, the absorption of electrons and ions by a macroparticle is described by introducing effective point sinks into the kinetic equations for plasma electrons and ions. Explicit expressions are derived for the potential distribution around a macroparticle and effective charges that determine the behavior of the potential at large distances taking into account collisions of electrons and ions with neutral buffer gas atoms. We consider the cases of a constant collision frequency and constant mean free paths of electrons and ions in the buffer gas. Numerical calculations are performed for dusty isothermal and nonisothermal plasmas in helium, neon, argon, krypton, and xenon at pressures of 10–1 to 10 4 Pa, which are typical of experiments with dusty plasmas. DOI: 10.1134/S1063776117100077
1. INTRODUCTION Theoretical investigation of the interaction of charged macroparticles in a plasma (electrolyte) remains topical in the physics of dusty plasmas [1–7]. Since dust particles or macroparticles acquire large charges in a plasma, numerical methods of the solution of nonlinear boundary-value problems or macroscopic methods like molecular dynamics methods are usually employed for determining the effective potential. As a result of such studies, many characteristic properties of screened potential of dust particles have already been established (see, for example, [8–21] and the literature cited therein). However, analytic relations are required for determining the interaction potential in the description of many interesting phenomena in experiments with dusty plasmas, such as the formation of a dust crystal, propagation of the dust–acoustic waves, and generation of nonlinear plasma–dust structures. Such investigations are also required for developing the theory of probes [22, 23]. In [24], the screening of a dust particle was investigated by solving numerically the Poisson equation and the kinetic equation for ions with a self-consistent
field and a collisional term. The problem was solved in the nonstationary formulation, and the distribution function was a function of four variables (time, r
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