Grain screening in semi-bounded plasmas
A.I. Momot and A.G. Zagorodny†
Kyiv National Taras Shevchenko University, Glushkova 2, 03022 Kyiv, Ukraine.
†Bogolubov Institute for Theoretical Physics, Metrolohichna 14-b, 03143 Kyiv, Ukraine.
Abstract. The screening potentials of single grain embedded into semi-bounded plasmas are calculated. Limiting cases of
collisionless plasma as well as plasma described in the drift-diffusion approach are considered. It is assumed that plasma
boundary does not absorb reflecting particles. We treat the grain as point-like particle with appropriate singular sink in the
equations describing plasma dynamics that makes it possible to take into account plasma particles absorption by grain. Such
model approach allows recovering the results for screening potentials calculated with regard to finite size of grain within the
linear approximation in the case of unbounded plasmas and can be easily extended to the case of bounded system. It turns out
to be that plasma dynamics can considerably influence the asymptotic behavior of screening potential. Modifications of such
potentials due to boundary influence are studied in detail. Particularly, the presence of asymptotic inversely proportional to
the third power of the distance parallel to the boundary is shown.
Keywords: dusty plasma, grain screening, semi-bounded plasma
PACS: 52.27 Lw
Let us consider semi-bounded weakly-ionized plasma (z > 0) with a stationary grain at the point~r0 = (0;0; z0). We
assume that the grain absorbs all encountered electrons and ions. If the ionization and recombination processes can be
neglected the continuity equations for plasma particles are the following
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