Dissipation in the Flow ofHe3-AandHe3-Bthrough a Narrow Rectangular Channel

Measurements are reported which relate to the dissipation and superfluid density of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$A$ and ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$B$ flowing through a long rectangular channel of cross section 48 μm × 2.86 mm at currents between 5 × ${10}^{-2\mathrm{}}$ g ${\mathrm{cm}}^{-2\mathrm{}}$ ${\sec }^{-1\mathrm{}}$ and 5 × ${10}^{-5\mathrm{}}$ g ${\mathrm{cm}}^{-2\mathrm{}}$ ${\sec }^{-1\mathrm{}}$ and at temperatures down to $\frac{T}{T_c}=0.52\mathrm{}$. The results show a complex velocity dependence in both phases.