CQL3D Time-Dependent Runaway Electron Discharge Dynamics, Including Self-Consistent Ampere-Faraday Equation, Radial Transport, and RF QL Diffusion

CQL3D provides a relativistic, finite-difference, bounce-averaged Fokker-Planck solution for the electron distribution f(v₀,theta₀,rho₀,t) under the influence of density/temperature variations induced, in this case, by a parameterized model for impurity stream from gas or pellet injection simulating plasma disruption or RE mitigation, and the toroidal electric field. For CQL3D, 6D phase-space is reduced to 3D by averaging over gyro-phase, bounce-phase, and toroidal angle in toroidal axisymmetric geometry. The solution is found self-consistently with the time-dependent Ampere-Faraday equations. We vary parameters controlling the amount and velocity of the impurity source, the rate of T_e-reduction, and the lowest T_e achieved, in order to clarify the role of these parameters for RE minimization. Effects of RF wave injection and internal excitation are considered, as a mechanism for enhanced pitch-angle scattering of electrons.

Supported by USDOE Grants ER54744 (CompX), DE-SC0016452 (GA SCREAM), and DE-FG02-95ER54309 (GA Theory).