MOBILITY OF NEGATIVE IONS ALONG VORTICES IN ROTATING SUPERFLUID HELIUM

The mobility of negative ions trapped on linear vortices in rotating superfluid helium has been measured by a time-of-flight technique in the temperature range 0.8°K<T<1.6°K. Measurements could not be extended below 0.8°K because, contrary to the present theory, the ion escape rate became too large. No evidence of direct trapping of positive ions by vortex lines was observed down to 0.4°K. The trapped-ion mobility is interpreted in terms of scattering of the ion by thermal distributions of quantized vortex waves and rotons localized about the vortex axis. © 1968 The American Physical Society.