Simulation of Neutral and Ion Sources and Sinks in Steady State C-2W Plasmas

On the C-2W experiment it is possible to maintain Field Reversed Configuration (FRC) plasmas in steady state for tens of milliseconds [1]. The main energy and momentum source terms are provided by neutral beam injection and electrode biasing and the main particle source term is neutral gas injection. The sink terms, which balance these sources in steady state, include charge exchange losses of the fast ions, parallel losses to the divertor, and wall contact. To study the interplay between these sources and sinks, kinetic simulations of neutral and ion transport during neutral beam injection and gas fueling have been performed using a particle transport model where atomic and molecular ions and neutrals co-evolve, with each species acting as the target background for Monte Carlo Collisions with the other species. In this study we compare the particle fueling rate required to maintain constant inventory in different C-2W fueling configurations.

[1] H. Gota et al., Nucl. Fusion 59, 112009 (2019).