The Role of Secondary Electron Collection in Box IEMP Coupling

Analytical models have been developed to estimate the secondary electron current collected at a biased land during box IEMP. The simple models are intended for the use of systems designers who must estimate the threat to active electronics during box IEMP and who may not have access to the large computer codes which simulate SGEMP. Separate theories apply to the nonself-consistent regime (when the collected charge does not greatly perturb the cavity fields) and the space-charge-limited regime (when the secondary electrons screen the potential near the land) . Analytical calculations for simple test cases compare well with self-consistent SGEMP computer simulations and with data from past experiments at an MBS facility. Underprediction of the response at biases above +100 V suggests that an undetermined physical mechanism becomes important at high biases.