Vortex Velocities in the O(n) Symmetric TDGL Model

An explicit expression for the vortex velocity field as a function of the order parameter field is derived for the case of point defects in the O(n) symmetric time-dependent Ginzburg-Landau model. This expression is used to find the vortex velocity probability distribution in the gaussian closure approximation in the case of phase ordering kinetics for a nonconserved order parameter. The velocity scales as $L^{-1}$ in scaling regime where $L\approx t^{1/2}$ and t is the time after the quench.