Abstract Details
Abstracts
Author: Eduardo Lascas Neto
Requested Type: Consider for Invited
Submitted: 2025-02-21 13:45:24
Co-authors: R. Jorge
Contact Info:
University of Wisconsin-Madison
1150 University Avenue
Madison, WI 53706
USA
Abstract Text:
Recent developments in stellarator optimization have shown that optimizing stellarator reactor designs to enable electron root operation is possible [1, 2, 3]. These optimization methods tune the ion and electron neoclassical transport to increase the plasma parameter space in which a positive electric field can occur. A plasma operation regime with a core-positive electric field provides good heavy impurity and helium ash exhaust [1]. Additionally, the transition between a positive and negative electric field observed in these regimes can potentially reduce turbulence [2] and induce the formation of a transport barrier if enough ExB shear is present. In this work, we use state-of-the-art JAX-developed neoclassical transport codes to go beyond the work in Ref. [1] and, for the first time, we obtain a new quasi-isodynamic (QI) configuration with a directly optimized positive radial electric field profile. This optimization method directly targets the core positive electric field shape and root transition position, providing reactor-desired neoclassical transport properties for tungsten and helium ash while maintaining good QI properties, low bootstrap current, and achieving large ExB shear.
[1] E. Lascas Neto at al., Journal of Plasma Physics. 2025;91(1):E24. doi:10.1017/S0022377824001466
[2] P. Helander, et al., Journal of Plasma Physics. 2024;90(6):175900602. doi:10.1017/S0022377824001004
[3] B.F. Lee et al. 2024, Nucl. Fusion 64 106054
Characterization: 1.0
Comments: