Parametric Study of a Physical Flashover Simulator

A physical flashover (FO) simulator has been developed by ONERA/DESP and CNES. The objective of this simulator is to represent the missing cells when testing small coupons in the laboratory. The aim of this paper is to present the results of a parametric study which has been performed on a sample constituted by a solar-array coupon made of six cells and a simulator constituted of a large surface of metallized polymeric film. Experiments were performed in the ONERA/DESP facility called JONAS which is a 9-m³ vacuum chamber equipped with a plasma source and a 10-keV electron gun. Electrostatic discharges (ESDs) occur in the inverted potential gradient (IPG) configuration obtained either by electrons or by plasma. The FO was characterized by measuring the neutralization current on the different surfaces with current probes. Therefore, we could get charge quantity, duration, and velocity. The surface potential of the coupon and the polymeric film were monitored before and after ESD by a potential probe, giving a good correlation with the amount of charges participating to the discharge. In order to determine what the limits of the FO are and what parameters can monitor it, we have studied different configurations: 1) electron or plasma IPG charging; 2) surfaces from 0.5 to 14 m²; 3) geometries-cylinder, ring, rectangular, and discontinuous surface; 4) primary arc locations-cell edge or interconnectors; and 5) absolute satellite capacitance values-between 300 pF and 300 nF. Analysis of the results is given for these configurations.