Abstract Details
Abstracts
Author: Carl R. Sovinec
Requested Type: Poster
Submitted: 2025-03-14 16:22:50
Co-authors: S. A. Patil, V. Cauilan
Contact Info:
University of Wisconsin-Madison
1500 Engineering Drive
Madison, Wisconsin 53706
USA
Abstract Text:
The NIMSTELL code is a redevelopment of NIMROD [1] for modeling macroscale dynamics in stellarators. It uses NIMROD's 2D nodal spectral element/1D finite Fourier series representation for its geometry and equilibrium-field data in addition to its evolved solution fields. At present, the modeling is resistive MHD with anisotropic thermal conductivity and viscosity. An option to expand magnetic vector potential in H(curl) elements leads to divergence-free magnetic field within elements with continuity of the normal component across element interfaces. The susceptibility of this representation to numerical instability at small resistivity values [2] prompted us to also implement the H1 representation of magnetic-field components that has been successful in NIMROD applications. Other recent developments include implementation of NIMROD's numerical interchange stabilization [3] and the completion of nonlinear terms. Benchmarking on linear tearing and ballooning in stellarator configurations is reported elsewhere [4]. Nonlinear verification compares sawtooth oscillations in a circular cross-section torus and interchange in a straight cylinder with results from NIMROD; deviations only develop late in the evolution for each case. Nonlinear saturation of (2,1) tearing in the W7-A stellarator geometry agrees with the JOREK results reported in [5]. We also demonstrate nonlinear tearing and island saturation in a modified version of the QA configuration from [6]. [1] Sovinec, Glasser, Gianakon, et al. J. Comput. Phys. 195, 355 (2004). [2] DE-SC0018642 Final technical report, https://doi.org/10.2172/2376548. [3] Sovinec, J. Comput. Phys. 319, 61 (2016). [4] Patil and Sovinec, 2024 APS DPP meeting, PP12.00002. [5] Nikulsin, Ramasamy, Hoelzl, et al., Phys. Plasmas 29, 063901 (2022). [6] Landreman and Paul, Phys. Rev. Lett. 128, 035001 (2022). This work is funded by U.S. Dept. of Energy awards DE-SC0024548 and DE-FG02-99ER54546.
Characterization: 4.0
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