Effect of impurities on dynamic dragging of dislocations

The rearrangement of the force of dynamic dragging of a dislocation due to its elastic interactio in with impurity atoms is analysed. The collisions of a moving dislocation with impurities excite additional vibrations of a dislocation line. Such vibrations lead to the appearance of extra parts to dissipative function and effective friction force of a dislocation which depend on location and concentration of impurities. This effect is one of the reasons of the influence of impurities observed in the experiments on the dynamic branch of the moving dislocation curve.