Comparison of dust charging between Orbital-Motion-Limited theory and Particle-In-Cell simulations
arXiv:1611.08658 · doi:10.1063/1.4935697
Abstract
The Orbital-Motion-Limited (OML) theory has been modified to predict the dust charge and the results were contrasted with the Whipple approximation [Tang and Delzanno, Phys. Plasmas 21, 123708 (2014)]. To further establish its regime of applicability, in this paper the OML predictions (for a non-electron-emitting, spherical dust grain at rest in a collisionless, unmagnetized plasma) are compared with Particle-In-Cell simulations that retain the absorption radius effect. It is found that for large dust grain radius relative to the plasma Debye length , the revised OML theory remains a very good approximation as, for the parameters considered (, equal electron and ion temperatures), it yields the dust charge to within accuracy. This is a substantial improvement over the Whipple approximation. The dust collected currents and energy fluxes, which remain the same in the revised and standard OML theories, are accurate to within .
15 pages, 2 figures. Copyright (2015) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Phys. Plasmas 22, 113703 (2015) and may be found at: http://scitation.aip.org/content/aip/journal/pop/22/11/10.1063/1.4935697