Abstract Details
Abstracts
Author: Torrin A Bechtel
Requested Type: Poster
Submitted: 2016-02-15 09:52:55
Co-authors: C. C. Hegna, N. A. Roberds, C. R. Sovinec, G. J. Hartwell, J. D. Hebert
Contact Info:
Unviersity of Wisconsin - Madison
1500 Engineering Dr
Madison, WI 53706
United States
Abstract Text:
It is desirable to understand the high beta properties of stellarator plasmas. To study these effects we use the nonlinear, extended MHD code NIMROD to model 3D magnetic topology evolution as beta is increased from vacuum. Such studies require the use of the newly recovered 3D semi-implicit operator to guarantee accurate temporal convergence. Spatial convergence studies have also been performed to ensure accurate final results. The configurations under investigation are an l=2, M=5 torsatron with geometry modeled after the Compact Toroidal Hybrid (CTH) experiment and an l=2, M=10 torsatron capable of having vacuum rotational transform profiles near unity. Finite beta plasmas are created using a volumetric heating source and temperature dependent anisotropic heat conduction and resistivity. The onset of MHD instabilities and nonlinear consequences are monitored as a function of beta as well as the fragility of the magnetic surfaces.*
*Research supported by US DOE under grant no. DE-FG02-99ER54546.
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