Evidence for a new discharge mechanism for dielectrics in a plasma

This paper proposes a bilayer discharge immediately within the outer surface layer of a dielectric in a plasma, rather than a discharge through or between spacecraft surface components. The bilayer consists of electrons that penetrate into the bulk and positive charge left on the surface as a result of electron depletion by secondary emission. If the bulk resistivity is sufficiently high and the incident electron flux from the plasma is sufficiently intense, then the potential gradients will exceed the breakdown field of the material. Simple modeling of the system shows good agreement with the laboratory results, suggesting that this form of discharge, in fact, does occur at magnetic substorm plasma densities and energies.