Optimization of nonlinear turbulence in stellarators

P. Kim, S. Buller, R. Conlin, W. Dorland, D. W. Dudt, R. Gaur, R. Jorge, E. Kolemen, M. Landreman, N. R. Mandell, D. Panici

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

We present new stellarator equilibria that have been optimized for reduced turbulent transport using nonlinear gyrokinetic simulations within the optimization loop. The optimization routine involves coupling the pseudo-spectral GPU-native gyrokinetic code GX with the stellarator equilibrium and optimization code DESC. Since using GX allows for fast nonlinear simulations, we directly optimize for reduced nonlinear heat fluxes. To handle the noisy heat flux traces returned by these simulations, we employ the simultaneous perturbation stochastic approximation (SPSA) method that only uses two objective function evaluations for a simple estimate of the gradient. We show several examples that optimize for both reduced heat fluxes and good quasi-symmetry as a proxy for low neoclassical transport. Finally, we run full transport simulations using the T3D stellarator transport code to evaluate the changes in the macroscopic profiles.

Original languageEnglish (US)
Article number2400036
JournalJournal of Plasma Physics
Volume90
Issue number2
DOIs
StatePublished - Apr 11 2024

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

Keywords

  • fusion plasma
  • plasma confinement
  • plasma simulation

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