Vortex nucleation in He II : an interesting distinction between the intrinsic and thermally activated nucleation mechanisms.

Nancolas, G. G. and Bowley, R. M. and McClintock, Peter V. E. (1996) Vortex nucleation in He II : an interesting distinction between the intrinsic and thermally activated nucleation mechanisms. Journal of Physics: Condensed Matter, 19 (2). L37-L41. ISSN 0953-8984

Abstract

The drift velocity of negative ions in He II, moving under the influence of electric fields large enough to quench the production of charged vortex rings, has been measured for a wide range of pressures and temperatures. It is found that, although the intrinsic (temperature-independent) vortex nucleation mechanism provides a major source of momentum loss, particularly at low pressures, the corresponding effect for the thermally activated (temperature-dependent) mechanism is immeasurably small. The underlying physical reasons for this interesting distinction remain unknown but some possible explanations are discussed.