In 2000 Harter et al. reported the first measurements of the enhancement of the heat capacity Delta C-Q equivalent to C(Q)-C(Q=0) of helium-II transporting a heat flux density Q near T-lambda. Surprisingly, their measured Delta C-Q was similar to 7-12 times larger than predicted, depending on which theory was assumed. In this report we present a candidate explanation for this discrepancy: unintended heat flux inhomogeneity. Because C(Q) should diverge at a critical heat flux density Q(c), homogeneous heat flow is required for an accurate measurement. We present results from numerical analysis of the heat flow in the Harter et al. cell indicating that substantial inhomogeneity occurred. We determine the effect of the inhomogeneity on Delta C-Q and find rough agreement with the observed disparity between prediction and measurement.
|State||Published - 2006|