AC ELECTRO-PLASTIC EFFECT IN SODIUM-CHLORIDE CRYSTALS

The effect of an ac electric field on the plastic strain rate is studied for sodium chloride single crystals. It is found that the strain rate increases when an ac electric field is applied, and the increment of the shear strain rate is nearly proportional to the square of the field intensity. It is shown that the effect can be explained by the model of direct interaction between the electric field and the charged dislocations. The dislocation charge is also estimated.