Particle in cell calculation of plasma force on a small grain in a non-uniform collisional sheath

The plasma force on grains of specified charge and height in a collisional DC plasma sheath is calculated using the multidimensional particle in cell code COPTIC. The background ion velocity distribution functions for the unperturbed sheath vary substantially with collisionality. The grain force is...

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Bibliographic Details
Main Author: Hutchinson, Ian Horner
Other Authors: Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Format: Article
Language:en_US
Published: IOP Publishing 2015
Online Access:http://hdl.handle.net/1721.1/95827
Description
Summary:The plasma force on grains of specified charge and height in a collisional DC plasma sheath is calculated using the multidimensional particle in cell code COPTIC. The background ion velocity distribution functions for the unperturbed sheath vary substantially with collisionality. The grain force is found to agree quite well with a combination of background electric-field force plus ion drag force. However, the drag force must take account of the non-Maxwellian (and spatially varying) ion distribution function, and the collisional drag enhancement. It is shown how to translate the dimensionless results into practical equilibrium including other forces such as gravity.