EFFECTS OF FINITE-AMPLITUDE FIELDS ON SUPERFLUIDITY

One of the most interesting phenomenon currently being studied in low temperature physics involves the effects of a, dynamic field, e.g. a f inite flow field, on material properties. Reppy and Tyler [1] observed an effect for finite alternating flows of superfluid helium in a poro us medium (vycor glass). Superfluid flows along interfaces result in t he generation of vorticity and the dissipation of the superfluid flow, as well as a significant effect, as large as 10%, on the superfluid m ass fraction. An important question is to what extent the effect depen ds on the type of porous media involved in the measurements. We have u sed a high porosity glass capillary array, with 3 mm long, 2 mu m diam eter, straight, smooth-wall pores, to address this question.