The Development of Pleiades, a Plasma MHD Equilibrium Solver, for the Magnetic Mirror*

We present a modified version of the Pleiades framework, originally created to model the Big Red Ball at the Wisconsin Plasma Physics Labratory [1], which can solve the free-boundary kinetic MHD equilibrium equations using an axisymmetric Green's function approach. As a part of Realta Fusion's high-field axisymmetric mirror modeling program, Pleiades has been modified to compute simple magnetic mirror MHD equilibrium solutions based on the kinetic pressure profiles calculated by a CQL3D-m transport simulation (CQL3D-m is the magnetic mirror version of the Fokker-Planck code, CQL3D). We show that these solutions satisfy the paraxial MHD equilibrium condition and accurately capture mirror ratio enhancements at high β. Pleiades has also been updated to utilize multiprocessing, increasing the computational efficiency of the framework by ~15 times, and can now perform cost-function optimizations of electromagnet geometries for a given set of desired magnetic field well parameters. These upgrades allow Pleiades to be used for magnetic mirror design and optimization.

Funding Acknowledgement:

This research was funded by Realta Fusion. This research also used resources of the National Energy Research Scientific Computing Center; a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 using NERSC award FES-ERCAP0026655.

References:

[1] E. Peterson et al. Nature Physics, Vol. 15 No. 10 (2019) Pg. 1095