April 15-17

Abstract Details

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Abstracts

Author: C. R. Sovinec
Requested Type: Poster
Submitted: 2019-02-22 13:33:26

Co-authors: C. M. Guilbault, T. A. Bechtel

Contact Info:
University of Wisconsin-Madison
1500 Engineering Dr.
Madison, WI   53706-1
USA

Abstract Text:
Stellarator experiments have demonstrated remarkable robustness to disruptive macroscopic dynamics. Nonetheless, they are subject to soft beta limits and to loss of equilibrium at sufficiently large Shafranov shift [1]. There are ongoing efforts to investigate the nonlinear evolution of stellarator dynamics [for example, 2-3], but representing the 3D equilibrium field and the dynamics is computationally challenging. A new effort is modifying the NIMROD code to make it efficient for modeling 3D configurations. The Fourier representation of the toroidal coordinate will be extended to represent toroidal variations in geometry and equilibrium fields. This extension implies that all Fourier components will be tightly coupled, even in linear computations and unlike what is assumed in the standard version of NIMROD. Thus, accurate and efficient solution of algebraic systems will be a premium, and this area has been our first focus in the development effort. Preprocessing will also require considerable development. Initial ideas on using geometry and field-profile results from the VMEC code [4] are presented for discussion.
[1] A. Weller, K. Y. Watanabe, S. Sakakibara, et al., NF 49, 065016 (2009).
[2] K. Ichiguchi, S. Sakakibara, S. Ohdachi, and B. A. Carreras, PPCF 55, 014009 (2013).
[3] T. A. Bechtel, C. C. Hegna, and C. R. Sovinec, Sherwood 2019 presentation.
[4] S. P. Hirshman, W. I. van Rij, and P. Merkel, CPC 43, 143 (1986).
*Work supported by US DOE grant DE-SC0018642.

Comments:
Please, place together with the poster presentation by T. A. Bechtel, C. C. Hegna, and C. R. Sovinec with that one appearing first.