Computation of Vacuum and 3-Torr IEMP Responses and Comparison with Benchmark Experiments

Calculation has been performed for the Harry Diamond Laboratory (HDL) benchmark IEMP Problem No. 21 under both vacuum and 3-torr conditions. The 3-torr air effects were simulated by a conductivity model and a particle-conductivity model, respectively, with the latter yielding superior results. The conductivity model only treats the secondary electrons by fluid conductivities and requires little computation time, but is known to be inadequate under high field conditions. The particle-conductivity approach treats secondaries as macro-particles at early times and resorts to a conductivity model when the ion density is high and fields are week. Present calculational results show much improved comparison with the experiment over the previous best results.