Analysis of shot-to-shot variability in post-disruption runaway electron currents for diverted DIII-D discharges

摘要: In DIII-D experiments, rapid termination by Ar-pellet injection sometimes produces a post-termination runaway electron (RE) current plateau, but this effect is highly non-reproducible on shot-to-shot basis, particularly for diverted target plasmas. A set of discharges analyzed with two MHD codes to understand the relationship between profile plasma and amplitude RE plateau. Using linear stability code GATO, correlation radial unstable n?=?1 mode just after observed appearance an plateau identified. Nonlinear NIMROD simulations test-particle calculations directly predict confinement times during disruption. With one exception, predicts better shots in which higher currents were DIII-D. But, variation primarily connected saturated not its profile. Still, both sets analyses support hypothesis that deconfinement fluctuations major factor variability plateaus, though additional factors such as seed cannot be ruled out.