Russell J. Donnelly
541-346-4226 (Tel)
541-346-5861 (Fax)

 <> ch11 ch12 ch13 ch14 ch15 ch16 ch17 ch18 ch19 ch20 ch21

The Observed Properties of Liquid Helium
at the Saturated Vapor Pressure

Chapter 20. Displacement Length and Vortex Core Parameter

The displacement and healing lengths and vortex core parameter of helium II are discussed in the appendix to a review article by Barenghi, Donnelly and Vinen 1. We give their spline fit and recommended values to the displacement length and recommended values of the core parameter a.

Table 20.1. Knots and coefficients for the displacement length in helium II as a function of log10(1-T/T). The displacement length is given by 10-8 times 10S where S is the value returned by the spline. The core parameter is 0.45 times the displacement length
 Knots Coefficients K( 1) = -8.00 C( 1) = 5.565787 K( 2) = -8.00 C( 2) = 4.059918 K( 3) = -8.00 C( 3) = 2.634489 K( 4) = -8.00 C( 4) = 0.7202562 K( 5) = -1.55 C( 5) = 0.5258717 K( 6) = -0.700 C( 6) = 0.3207715 K( 7) = -0.530 C( 7) = 0.3264315 K( 8) = 0 K( 9) = 0 K(10) = 0 K(11) = 0

Table 20.2. Table of recommended values of the displacement length of helium II.

 T90 (K) (cm) 1.30 3.072E-8 1.35 3.183E-8 1.40 3.303E-8 1.45 3.432E-8 1.50 3.568E-8 1.55 3.710E-8 1.60 3.855E-8 1.65 4.010E-8 1.70 4.181E-8 1.75 4.386E-8 1.80 4.649E-8 1.85 4.998E-8 1.90 5.478E-8 1.95 6.171E-8 2.00 7.247E-8 2.02 7.862E-8 2.04 8.647E-8 2.06 9.682E-8 2.08 1.111E-7 2.10 1.320E-7 2.12 1.654E-7 2.14 2.281E-7 2.16 4.040E-7 2.162 4.426E-7 2.164 4.912E-7 2.166 5.546E-7 2.168 6.416E-7 2.170 7.701E-7 2.172 9.837E-7 2.174 1.432E-6 2.176 3.373E-6 2.1761 3.691E-6 2.1762 4.095E-6 2.1763 4.630E-6 2.1764 5.377E-6 2.1765 6.517E-6 2.1766 8.536E-6 2.1767 1.350E-5

C. F. Barenghi, R. J. Donnelly, and W. F. Vinen, “Friction on Quantized Vortices in Helium II. A Review,” J. Low Temp. Phys. 52, 189-247 (1983).

 <> ch11 ch12 ch13 ch14 ch15 ch16 ch17 ch18 ch19 ch20 ch21