The He II-He I Transition in a Heat Current
Simple thermodynamic arguments1,2 lead one to believe that in the presence of a counterflow velocity the transition from He II to He I should occur at temperatures somewhat lower than the λ temperature at saturated vapor pressure. The most convenient method of generating a counterflow velocity is to apply a heat flux Q in an otherwise undisturbed column of He II. However, the application of a heat current has certain concomitant effects which have not been included in the theoretical studies so far and which may alter the existing results both qualitatively and quantitatively. First, when a heat flux is present there is invariably a temperature gradient, and second, for moderate Q values the thermal resistance is in large part due to a tangled mass of vortex lines in the fluid. Unfortunately, there does not appear to be any simple way to modify the existing theory to take account of these effects.
KeywordsHeat Flux Saturated Vapor Pressure Vortex Line Heat Current Large Systematic Error
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- 8.F. Vidal, M. Le Ray, M. François, and D. Lhuillier, this volume.Google Scholar