Optimizing Stellarators Against Energetic Particle Loss with DESC*

Energetic particles play an important role in maintaining a high plasma temperature needed for self-sustained nuclear fusion.  Consequently, enhancing the confinement of these particles is pivotal for increasing their energy contribution to the bulk plasma and minimizing heat fluxes on plasma facing components. However, due to the vast design space offered by stellarators, finding configurations with favorable energetic particle confinement becomes a complex optimization problem.

To this end, we implement energetic particle proxies and c in the DESC stellarator equilibrium and optimization suite [1,2,3,4]. These proxies measure the neoclassical transport of energetic particles. As highlighted by Velasco et al, there is a strong correlation between these proxies and the performance of stellarators [5]. By adding the calculation of  and c parameters to DESC, we find stellarators optimized for reduced energetic particle transport.

[1] Panici, D. et al (2023). The DESC Stellarator Code Suite Part I: Quick and accurate equilibria computations.

[2] Conlin, R. et al. (2023). The DESC Stellarator Code Suite Part II: Perturbation and continuation methods.

[3] Conlin, R. et al. (2023). The DESC Stellarator Code Suite Part II: Perturbation and continuation methods.

[4] Dudt, D. & Kolemen, E. (2020). DESC: A Stellarator Equilibrium Solver.

[5] J.L. Velasco et al 2021 Nucl. Fusion 61 116059