Hydrodynamic experiments in superfluid 3He

In this paper, the measurements of the hydrodynamic quantities, superfluid density and viscosity in liquid 3He are described. At Cornell, the technique developed by Andronikashvili was adapted for the measurement of the superfluid density in liquid 4He. Liquid helium is contained in a cell formed by parallel circular plates of radius R. The spacing, h, between the plates and the frequency of oscillation are chosen so that the viscous penetration depth is greater than the spacing between the plates. The data produced by the Andronikashivli experiment consist of the period, P, of the oscillator, the drive voltage, D, required to maintain a constant amplitude of oscillation and the susceptibility of either NMR or CMN thermometers. Temperatures are obtained from the susceptibility data in the conventional manner by assuming Curie law behavior for temperatures down to the transition. An expression for torque, L, produced by the fluid in the Andronikashvili cell during torsional oscillation is obtained. In the Fermi liquid region above the transition, the viscosity is expected to be proportional to 1/T2 on the basis of theory and previous measurement. Measurement of normal fluid density, anisotropy of the superfluid density, B phase superfluid density, and B phase normal fluid viscosity were carried out. The main accomplishments of the measurement to date have been the clear demonstration of the anisotropy of A-phase superfluid density and the high resolution measurement of B-phase normal fluid shear viscosity in the immediate neighborhood of the transition. (Kato, T