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frc_simsnimrod.pdf2007-03-28 15:55:16Richard Milroy

FRC Simulations using the NIMROD Code

Author: Richard D Milroy
Requested Type: Consider for Invited
Submitted: 2006-12-17 14:17:44

Co-authors: A.I.D. Macnab, C.C. Kim, C.R. Sovinec

Contact Info:
University of Washington
14700 NE 95th Street
Redmond, WA   98052

Abstract Text:
The Plasma Science and Innovation Center (PSI-Center) is benchmarking and refining the NIMROD code for simulations of field-reversed configurations (FRCs). The NIMROD code can resolve highly anisotropic heat conduction and viscosity [C.R. Sovinec, et al., JCP 195, 355 (2004)]. This combined with its ability to include two-fluid effects, allows us to capture more detailed physics than previous calculations.
When the tangential electric field on the end boundaries (open field lines) is set to zero and the Hall term is included in the calculation, the open field-line plasma spins up due to end-shorting effects, which in turn couples to the main FRC plasma through shear viscosity. The spin-up rate is found to be sensitive to the open field-line plasma profile. Results of these calculations will be compared with previous analysis and experimental observations.
We are also investigating recent observations [H.Y. Guo, et al., Phys. Rev. Lett. 95, 175001 (2005)] that imply that a small toroidal field could help stabilize the n=2 rotational instability. Preliminary results indicate that a combination of a relatively weak toroidal magnetic field and the inclusion of the Hall term in the calculation can lead to a change in the character of the mode and a dramatic reduction to its growth rate.
Recent modifications to the radial boundary conditions capture most of the effects of multiple discrete coils found in many FRC experiments. With this enhancement combined with the ability to include Hall physics, we have begun testing the ability of the code to predict FRC formation and translation, as well as toroidal field generation due to non-symmetric formation.

Characterization: E10

Please group this paper with other PSI-Center papers. That is with authors, George Marklin, Charlson Kim, Brian Nelson, ...

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Innovative Confinement Concepts Workshop
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