Suppression of Prebreakdown Emission Activity Inside the On-board Spacecraft Equipment by Local Polymerization in Discharge

The paper is devoted to the problem of secondary arcing inside the spacecraft power equipment operating at voltages of 100 V and higher that exceeds essentially the vacuum arc voltage drop. To mitigate arcing, populated circuit boards are covered with protecting dielectric films. Defects in films play a role of triple junctions lowering hold-off voltages and causing breakdowns and arcing. Experiments with artificial defects revealed dependence of the arc ignition voltage under plasma on the defect size which can be considered as a criterion for arc risk estimation. Low-current discharge burning on defects in chemically active gas mixtures leads to local polymerization and discharge extinction. Limits of the approach for arc mitigation are analyzed in the article on the basis of experimental data.