Electrical Simulation of Electrostatic Discharges in Dielectrics

The body replacement currents on a cylindrical conducting can have been measured for an arc discharge excitation that simulates a punchthrough breakdown of a charged dielectric sheet. These measurements are compared to calculated responses for three cases: (1) an arc discharge for essentially the same geometry as the experiment, (2) a uniform electron emission from the end of the can representing a blow off discharge, and (3) a capacitive direct injection drive from the end of the can representing an electrical simulation of the blowoff process. The responses are compared using appropriate scaling relationships. When the results are scaled to the same amount of released charge and the same pulse shape, the surface currents created by the outward emission of charge and the capacitive direct injection drive are more than an order of magnitude larger than the measured and calculated responses for the arc discharge, except very close to the breakdown point. Assuming that a significant fraction of the charge involved in a breakdown process is emitted outward, it is concluded that the major body-current responses of a spacecraft due to a dielectric discharge can be simulated by a capacitive direct injection drive electrical test. The current practice of using arc discharges to simulate body responses due to electrostatic discharges is, in general, not as good a technique as a capacitive direct injection drive.