Study of a simulated sustained edge-current driven spheromak in SSPX geometry

The sustainment of current in the core of a toroidal plasma by electrostatic edge-current drive requires the radial transport of current across imperfect magnetic surfaces. Full sustainment concurrent with adequate energy confinement has been difficult to find either experimentally or numerically. A NIMROD simulation in SSPX geometry with fixed bank current has recently been extended to nearly an L/R time, and exhibits apparent steady-state cycles with time-averaged sustainment: intervals of closed surfaces and peaked temperature profiles, punctuated by short bursts with voltage spikes and open surfaces. The confinement properties of this simulation will be analysed, and results presented.