Time Dependence of Vortex-Ring Creation in He II

Abstract

Measurements of vortex-ring current created by ions in pulsed electric fields of durations ranging from ${10}^{-6\mathrm{}}$ to ${10}^{-4\mathrm{}}$ seconds were made in a temperature range of 0.55 to 0.70 K. The results show that the number of vortex rings created is an exponential function of time as predicted by Donnelly and Roberts. However, the velocity dependence of measured nucleation probabitilities is only in qualitative agreement with the theory.