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Title: Intrinsic fluctuations of dust grain charge in multi-component plasmas

A master equation is formulated to model the states of the grain charge in a general multi-component plasma, where there are electrons and various kinds of positive or negative ions that are singly or multiply charged. A Fokker-Planck equation is developed from the master equation through the system-size expansion method. The Fokker-Planck equation has a Gaussian solution with a mean and variance governed by two initial-value differential equations involving the rates of the attachment of ions and electrons to the dust grain. Also, a Langevin equation and a discrete stochastic method are developed to model the time variation of the grain charge. Grain charging in a plasma containing electrons, protons, and alpha particles with Maxwellian distributions is considered as an example problem. The Gaussian solution is in very good agreement with the master equation solution numerically obtained for this problem.
Authors:
 [1]
  1. Department of Mechanical and Aerospace Engineering, The University of Alabama in Huntsville, Huntsville, Alabama 35899 (United States)
Publication Date:
OSTI Identifier:
22251906
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ALPHA PARTICLES; ANIONS; DUSTS; ELECTRONS; FLUCTUATIONS; FOKKER-PLANCK EQUATION; LANGEVIN EQUATION; MATHEMATICAL SOLUTIONS; PLASMA; PROTONS