Motion of Negative Ions Along Quantized Vortex Lines

Abstract

The motion of negative ions trapped in quantized vortex lines in rotating helium II has been measured down to 0.8°K by means of a time-of-flight apparatus. Trapped ions always move more slowly than free ions at the same temperature. The contribution of the extra retardation due to the vortex line appears to vary as $\exp (-\frac{\Delta }{\mathrm{kT}})$, where $\frac{\Delta }{k}=1.87\mathrm{}°$K between 0.8 and 1.5°K.