Ionic Mobility in Solid Dielectrics

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Abstract
1. It is assumed that ionic mobility in solid dielectrics is controlled by a combined resistance of viscosity, elasticity and solid friction. 2. Under this assumption ionic mobility under alternating electric stress is calculated. It appears from the formulae that there is a finite contribution due to ions toward both the dielectric constant and loss factor. In the range of technical and acoustical frequencies both are in first approximation independent of frequency. The loss factor, controlled by the solid friction, is equivalent to an a.c. conductivity several orders higher than the d.c. conductivity, as known from observation. 3. Applying the same conception to ionic mobility in a constant field of high intensity, it appears that ions cover only part of their travel by a viscous flow, a small fraction being due to elastic displacements. This latter increases with the field strength. The energy stored during this displacement is finally converted into vibratory kinetic energy of the ion, thus enabling it to accumulate energy and finally ionize. The theory shows that this process becomes appreciable at a field strength between 104 and 105 v/cm in agreement with observations on the increase with field strength of the conductivity.