Coupled EM-PIC/Radiation Transport Simulations of HERMES Courtyard Experiments
A suite of coupled computational models for simulating the radiation, plasma, and electromagnetic (EM) environment in the High-Energy Radiation Megavolt Electron Source (HERMES) courtyard has been developed. In principle, this provides a predictive forward-simulation capability based solely on measured upstream anode and cathode current waveforms in the Magnetically Insulated Transmission Line (MITL). First, 2D R-Z ElectroMagnetic Particle-in-Cell (EM-PIC) simulations model the MITL and diode to compute a history of all electrons incident on the converter. Next, radiation transport simulations use these electrons as a source to compute the time-dependent dose rate and volumetric electron production in the courtyard. Finally, the radiation transport output is used as sources for EM-PIC simulations of the courtyard to com- pute electromagnetic responses. This suite has been applied to the November 2016 trials, shots 10268-10313. Modeling and experiment differ in significant ways. This is just the first iteration of a long process to improve the agreement, as outlined in the summary.