Evidence for an energy barrier impeding the creation of quantized vortices in He II.

Hendry, P. C. and Lawson, N. Stuart and Williams, Charles D. H. and McClintock, Peter V. E. and Bowley, R. M. (1987) Evidence for an energy barrier impeding the creation of quantized vortices in He II. Japanese Journal of Applied Physics, 26 (Supple). pp. 73-74. ISSN 0021-4922

Abstract

The rate nu at which negative ions create quantized vortex rings in isotopically pure He II has been measured for temperatures 70 < T < 500 mK, pressures 12 < P < 19 bar and electric fields 10^4 < E < 10^S V/m. The result can be taken to imply the existence of an energy barrier impeding the nucleation process of ~3K.