Short-Circuit Currents in Charged Dielectrics and Motion of Zero-Field Planes

When a previously charged dielectric is short circuited, discharge currents result due to the movement of charge carriers in the field of the space charge. It is shown for plane-parallel geometry that the discharge current is given by the product of charge density at, and velocity of, the zero-field plane. The resulting expression includes the displacement current. It can also be applied to the case where the dielectric is exposed to a beam of penetrating radiation; it then allows one to evaluate the effect of space charge on the external current.