Abstract Details
Abstracts
Author: Carl Sovinec
Requested Type: Poster
Submitted: 2024-04-11 16:24:33
Co-authors: S.Patil
Contact Info:
University of Wisconsin-Madison
1500 Engineering Drive
Madison, Wisconsin 53706-1
USA
Abstract Text:
Time-dependent numerical computations can be used to predict the evolution of stellarators due to macroscale instabilities, starting from magnetohydrodynamic (MHD) equilibria or from vacuum fields, subject to heating. Although non-ideal MHD simulations are widely used for tokamaks, RFPs, and other nominally symmetric configurations, modeling the geometry of stellarators poses greater demands with respect to numerical resolution, hence computational cost. To address these challenges, NIMSTELL uses a nodal spectral-element representation, where the degree of polynomials within a 2D plane of elements and the 1D Fourier expansion for a generalized toroidal angle are specified at runtime. This allows either finite-element (h) or spectral (p) refinement for numerical convergence. NIMSTELL differs from NIMROD in having a 3D mapping from elements to physical coordinates. It has also been developed to evolve vector potential in the H(curl) space instead of expanding magnetic-field components in the H1 space. Although the vector-potential representation completely avoids numerical divergence error, we find that some computations with distorting meshes generate numerical instabilities that do not materialize with an optional H1 expansion of magnetic-field components. Possible approaches for stabilizing the vector-potential representation are presented. This work is supported by US DOE through grants DE-SC0018642, DE-FG02- 99ER54546, and DE-SC0024548.
Comments:
Please, place this poster together with the one by Sanket Patil.