Runaway electron suppression in MST tokamak plasmas with RMP: simulation and experiment*

Nonlinear MHD simulations using the NIMROD code have provided an explanation for the differing effects of $m=1$ and $m=3$ resonant magnetic perturbations (RMPs) on runaway electron (RE) confinement in Madison Symmetric Torus (MST) tokamak plasmas. Correlating experiments with simulated magnetic topology shows that REs are suppressed only when the applied RMP imposes magnetic chaos in the outer region of the plasma [Munaretto, et al., NF 60, 046024 (2020)]. Without an RMP, discharges with $q(0)<1$ and $2

*Work supported by US DOE grants DE-SC0020245 and DE-SC0018001.