On "radiation-free" states in transient motion of dislocations

The existence of "radiation-free" states in transient motion of dislocation s is investigated. By analyzing an edge dislocation jumping from rest to a supersonic speed, we see that the Mach fronts disappear at v(d)=root 2c(2) because at this dislocation velocity, the pole singularity in the complex p lane is replaced by a removable one. However, there exist radiated stress w aves propagating with velocity c(2), as well as c(1). Also, due to radiated longitudinal waves, there is a "force" required to be supplied to sustain such a motion. (C) 2001 American Institute of Physics.