Particle-in-cell Modeling of Magnetic Mirror Confinement Devices with VPIC

Magnetic mirrors have recently been the subject of renewed interest, both as a neutron source and a fusion concept, in large part due to the advent of high-temperature superconductors making much stronger magnetic fields feasible to maintain and some promising results from the GDT experiment in Novosibirsk [1]. A new high-field mirror experiment is under construction at U. Wisc.-Madison. As such, computational modeling capabilities are necessary to supplement and guide ongoing experimental research. We present simulations of magnetic mirror systems in the fully-kinetic particle-in-cell (PIC) VPIC code and in the fluid electron, PIC ion Hybrid-VPIC. Fully kinetic PIC simulations of the expander region are in excellent agreement with collisionless guiding center theory [2]. Simplified two-dimensional simulations of a full device include the self-consistent ambipolar potential, a population of injected fast sloshing ions, Coulomb collisions, and DT fusion burn. Loss rates and confinement are analyzed.

[1] Ivanov and Prikhodo, Gas-dynamic trap: An overview of the concept and experimental results. Plasma Physics and Controlled Fusion. 2013.

[2] Wetherton et al., A drift kinetic model for the expander region of a magnetic mirror. Phys. Plasmas. 2021.