Improved three-dimensional hybrid kinetic PIC simulations of FRCs in compression

Helion’s approach to fusion involves compressing self-organized field reversed configuration (FRC) plasmoids to thermonuclear temperatures and densities. The compression simulations encounter numerical challenges associated with using hybrid kinetic PIC simulations that arise due to the growing density dynamic-range throughout the compression ramp. Hybrid simulations typically resolve the ion inertial length or ion skin depth and historically have issues that arise due to the stringent whistler time-stepping constraint. This work presents compression simulations though large dynamic range that include scaling the numerical density floor and field sub-stepping in conjunction with the time-varying external field. Results from improved compression simulations are presented which can achieve a larger dynamic range than previous simulations and show FRC stability and lifetime performance through compression.