Charged-Vortex-Ring Creation by Ions in Superfluid Helium

Abstract
The critical-threshold electric fields and the critical velocities for the formation of charged vortex rings have been measured at temperatures 0.35<T<1°K. Below T=0.85°K, two different thresholds are shown to exist, connected with two different processes of formation. These two processes are found to be detectable only when a stability condition is satisfied.