Experiments on Magnetically Driven Superflow inHe3-A1

Magnetically generated superflows were observed in the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$A_1$ phase at pressures of 22.3 to 25.9 bars in magnetic fields of 3.7 to 5.5 kG. A two-fluid model is used to calculate the magnitude of the magnetic fountain effect. Critical-velocity effects were observed for sufficiently high flow rates. The critical velocity in the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$A_1$ phase was found to be 0.21 mm/sec in the reduced temperature range 0.0004 to 0.008. A threshold field gradient for the magnetic fountain effect was observed in part of the $A_1$ phase and may be evidence of fluctuations above $T_{c2\mathrm{}}$.