Effect of electron emission on the charge and shielding of a dust grain in a plasma: A continuum theory
- Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)
- Max-Planck-Institut fuer extraterrestrische Physik (Germany)
The continuum approximation is used to analyze the effect of electron emission from the surface of a spherical dust grain immersed in a plasma on the grain charge by assuming negligible ionization and recombination in the disturbed plasma region around the grain. A parameter is introduced that quantifies the emission intensity regardless of the emission mechanism (secondary, photoelectric, or thermionic emission). An analytical expression for the grain charge Z{sub d} is derived, and a criterion for change in the charge sign is obtained. The case of thermionic emission is examined in some detail. It is shown that the long-distance asymptotic behavior of the grain potential follows the Coulomb law with a negative effective charge Z{sub eff}, regardless of the sign of Z{sub d}. Thus, the potential changes sign and has a minimum if Z{sub d} > 0, which implies that attraction is possible between positively charged dust grains.
- OSTI ID:
- 21075623
- Journal Information:
- Journal of Experimental and Theoretical Physics, Vol. 106, Issue 1; Other Information: DOI: 10.1007/s11447-008-1014-3; Copyright (c) 2008 Pleiades Publishing, Ltd; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7761
- Country of Publication:
- United States
- Language:
- English
Similar Records
Hyperdiffusion of dust particles in a turbulent tokamak plasma
On vapor shielding of dust grains of iron, molybdenum, and tungsten in fusion plasmas