Emission of elastic waves from a dislocation in a 2-D discrete lattice

A dislocation moving in a lattice emits elastic waves, as it accelerates an d decelerates due to the lattice periodicity. In this work, simulations of this process in a 2-D discrete square lattice are presented. Under a small applied stress, the dislocation motion from an unstable position to the nex t stable position is accompanied by emission of dipolar waves, followed by quadrupolar emission when it oscillates around the stable position. When th e applied stress is larger than 70% of the Peierls stress, the dislocation overcomes the Peierls hills, and after moving a few atomic distances it ach ieves a steady motion with alternating forward motion and "hesitation" or o scillation, accompanied by radiations of dipolar and quadrupolar waves. (C) 2001 Elsevier Science B.V. AH rights reserved.