Note on Theories of Time-Varying Space-Charge Polarization

Abstract

The nonlinearity of the differential equations governing space-charge buildup or decay cause the principle of superposition to be inapplicable. Thus, charging and discharging curves should differ and depend strongly on applied voltage when space-charge formation is appreciable. Two approximate theories of space-charge formation and decay are compared, and it is found that one of their main differences is that one has been partly linearized while the other has not. Finally, it is mentioned that of the several theories of the ac response of materials with space charge, only one has not been linearized; hence, it is the only one applicable for applied voltages above about kT/e.