A condition of the static electric field for a system of multi-dielectrics with finite resistivities and its applications

There is no absolutely insulating material. The electric field in a system involving two or more dielectrics are not static; even equilibrium state may not arrive if one of the dielectrics is a gas. This is attributed to the charging up at the interfaces between the dielectrics. The phenomenon has been observed with some devices, where the interfaces are present in a region of strong electric fields (above 50 kV/cm), e.g. in MicroStrip Gas Chambers (MSGC) and some electrostatic accelerators. A condition of the static electric field for such a system has been found based on the physical properties of the dielectrics [1]. Another one is proposed here. It is relavant to the geometries of the dielectrics. As an application a design of MSGC without surface charging is proposed.