FDTD Modeling of Internal Electrostatic Discharge Events Coupled to High Frequency Antennas

Satellites that orbit planets with radiation belts are subjected to experience internal electrostatic discharge (IESD) events as they interact with charged particles. When charge accumulation exceeds the threshold of the dielectric material on the spacecraft, large discharges occur. The discharges generate electromagnetic pulses that couple to the antennas and induce high voltages. Protection from these discharges is of paramount concern for instrument fidelity of the spacecraft. Modeling the spacecraft and simulating these IESD events using a Maxwell's equations solver can describe how IESDs couple to the antennas of the spacecraft and thus provide information on how to properly protect the instruments from these high voltages. In particular, the finite-difference time-domain (FDTD) method offers advantages for this application over other electromagnetic numerical solvers because in a straight-forward manner it can simulate wideband transient pulses and also accurately solve near-field effects. A generalized analysis method is proposed and carried out in which an FDTD model is used to obtain transfer functions for IESD's occurring at hundreds of different locations on the spacecraft, which are then linearly combined to represent a wide variety of possible scenarios.