Particle-in-Cell with Monte Carlo Collisions Gun Code Simulations of a Surface-Conversion H^- Ion Source

E. Chacon-Golcher ^1*, K. J. Bowers ²

We present an extended update on the status of a particle-in-cell with Monte Carlo collisions (PIC-MCC) gun code developed at Los Alamos for the study of surface-converter $H^-$ ion sources. The program is fully kinetic. Some of the program's features include: solution of arbitrary electrostatic and magnetostatic fields in an axisymmetric ($r$,$z$) geometry to describe the self-consistent time evolution of a plasma; simulation of a multi-species ($e^-$, $H^+$, $H_2^+$ , $H_3^+$ , $H^-$) plasma discharge from a neutral hydrogen gas and filament-originated seed electrons; full 2-dimensional ($r$,$z$) 3-velocity ($v_r$, $v_z$, $v_\phi$) dynamics for all species; detailed collision physics between charged particles and neutrals and the ability to represent multiple smooth (not stair-stepped) electrodes of arbitrary shape and voltage whose surfaces may be secondary-particle emitters ($H^-$ and $e^-$). The status of this development is discussed in terms of its physics content and current implementation details.