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Two-fluid Plasma-Neutral Model Development and Application

Author: Eric T. Meier
Requested Type: Poster Only
Submitted: 2009-12-04 22:36:55

Co-authors: U. Shumlak*, V.S. Lukin**

Contact Info:
PSI-Center, UW, Seattle, WA
5115 39th Ave. NE
Seattle, WA   98105
USA

Abstract Text:
* PSI-Center, UW, Seattle,WA
** Space Sciences Division, NRL, Washington, D.C.
A two-fluid model for capturing the physics of interacting and reacting plasma and neutral fluids has been derived by taking moments of the Boltzmann equation and accounting for the reaction physics stemming from collisional species conversion. (The derivation is similar to that of Braginskii [1], but is generalized to include reactions.) Zero electron mass, charge neutrality, and hydrogen plasma are assumed. The model has separate densities, temperatures, and velocities for the two (plasma and neutral) fluids. In addition to tracking the changes in fluid densities due to species conversion, the associated momentum and energy exchange are also tracked. The essence of the exact model is retained (and improvements to the fluid closures are in progress) in an implementation in the HiFi implicit spectral element code [2,3]. The implementation is based on visco-resistive MHD for the plasma and viscous Euler for the neutral gas. Temperature-dependent charge exchange, ionization and recombination reactions are modeled. Development of this model is part of an effort by the PSI-Center to properly capture neutral gas effects in ICC plasmas. The model has been applied to qualitatively study FRC acceleration through neutral gas [4]. Model details and progress in applying the model will be described. Application efforts will focus on two issues: 1) Momentum and kinetic energy exchange in the highly dynamic plasma of a coaxial plasma accelerator with attention to critical ionization velocity (CIV) effects; 2) Neutral background effects on confined plasmas.
[1] S.I. Braginskii, Rev. Plasma Physics, vol. 1, p. 205, 1965;
[2] V.S. Lukin, PhD Dissertation, Princeton University, 2007;
[3] V.S. Lukin, 2010 ICC presentation;
[4] B.A. Nelson, 2010 ICC presentation.

Characterization: E10

Comments:
Place with other Plasma Science and Innovation Center (PSI-Center) posters.