Lumped Element Circuit Model of Pulsed Power for PIC Simulation of High Power Microwave Tubes

Summary form only given. When simulating high power microwave tubes, tube operation can influence the pulsed power network as well as vice versa. Commonly used approximations, such as a wave emitting/absorbing boundary condition, do not capture the dynamic mutual interaction of pulsed power with the microwave tube. For example, impedance collapse due to diode closure will cause both a drop in the pulsed power input voltage and increased current draw, an effect which might be simulated incorrectly if the wave emitting boundary condition assumes the pulsed power produces a prescribed voltage. We have modified the ICEPIC code to include lumped circuit elements as described in Taflove but recast into modifications of the current on the computational mesh rather than modified electric field updates. Using these lumped elements we have created an LC circuit model of the pulsed power drive: this model produces a flat-top voltage profile across a resistive load similar to experimental results. We also compare LC-circuit driven magnetron simulations with wave-driven simulations and experiment. We also study introducing mutual inductances between stages of the pulsed power by placing inductors adjacent to each other in simulation