Field Stability Investigation of Electrical Conductivity of a Dielectric Filled with a Conductive Compound

Abstract

The paper is devoted to the problem of space onboard equipment stability to the factors of internal charging. Spacecraft dielectrics should have increased conductivity to exclude physical possibility of electrostatic discharges in them when exposed to near-Earth plasma electron radiation. It is possible to achieve an increase in the conductivity of dielectrics by introducing a finely-divided conductive compound into them; its concentration should be carefully controlled in order to remain near the percolation threshold. However, during preliminary research, it has been found out that application of voltage to metal-dielectric-conductor structures (MDM), manufactured on the basis of such dielectrics, may lead to spontaneous instabilities of the electric current passing through the dielectric. A method for testing nano-conductive dielectrics of this type for long-term current flow has been developed. The purpose of this paper is to explain the mechanism of a significant decrease (up to 10 or more times) in the conductivity of dielectrics with increased conductivity during the flow of high currents and to develop a physical model on this basis that would allow to explain the observed phenomenon. Such a model will make it possible to predict the life time of dielectrics, working not only in near-Earth plasma, but also during interplanetary missions (for example, to Jupiter, where the flows of charged particles are three orders of magnitude higher than the near-Earth ones).