Collisional effects on nonlinear ion drag force for small grains
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Hutchinson_Collisional effects.pdf
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1.36 MB
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768a5c4c1e81ad17d26eb21268a0ee70
Author(s)
Haakonsen, Christian Bernt
Hutchinson, Ian Horner
Date Issued
August 2013
Journal
Physics of Plasmas
Publisher
American Institute of Physics (AIP)
Citation
Hutchinson, I. H., and C. B. Haakonsen. “Collisional Effects on Nonlinear Ion Drag Force for Small Grains.” Phys. Plasmas 20, no. 8 (2013): 083701.
Version
Author's final manuscript
Abstract
The ion drag force arising from plasma flow past an embedded spherical grain is calculated self-consistently and non-linearly using particle in cell codes, accounting for ion-neutral collisions. Using ion velocity distribution appropriate for ion drift driven by a force field gives wake potential and force greatly different from a shifted Maxwellian distribution, regardless of collisionality. The low-collisionality forces are shown to be consistent with estimates based upon cross-sections for scattering in a Yukawa (shielded) grain field, but only if non-linear shielding length is used. Finite collisionality initially enhances the drag force, but only by up to a factor of 2. Larger collisionality eventually reduces the drag force. In the collisional regime, the drift distribution gives larger drag than the shift distribution even at velocities where their collisionless drags are equal. Comprehensive practical analytic formulas for force that fit the calculations are provided.
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Massachusetts Institute of Technology. Plasma Science and Fusion Center
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1063/1.4818144
