Arcing on Solar Generators by Collection of Ionospheric Plasma Currents

There are several well-known possibilities to trigger a secondary arc on solar arrays by the creation of conductive plasma produced in the gap between two solar cell strings. It could be by electrostatic discharges due to an inverse potential gradient condition, micrometeoroid impacts, or laser impacts. The development of electrical propulsion for satellites requires higher voltages on solar arrays. These voltages strongly modify the plasma-satellite interactions, especially by increasing the collection of plasma currents. By studying this plasma collection current on solar cell samples, we have detected secondary arcs between two strings without any triggering event as previously described. Focusing on this event, we found that a series of physical phenomena may lead to the secondary arcing situation: heating by plasma current collection, outgassing, Paschen discharge conditions, and then secondary arcing. We have reproduced on solar cell-like samples what occurs when an arc starts and the conditions for its occurrence. Thereby, we have defined when this phenomenon is able to happen on real solar arrays.