Turbulence Experiments in Superfluid 3He at Very Low Temperatures

Over the past few years, the experimental study of superfluid turbulence has made very significant, advances following the discovery of turbulence in the B-phase of superfluid He-3. Experiments in superfluid He-3 are far more cryogenically challenging than in He-4 since the temperatures required are of order a thousand times lower. However, He-3 has some advantages. The main advantages come from the ease of vortex detection at low temperatures. In particular, vortices in He-3 have a large cross-section for Andreev Scattering quasiparticle excitations. This property along with ultra sensitive quasiparticle detection techniques, allows superfluid turbulence experiments even in the very low temperature limit. In this chapter, we first give a brief background to the cryogenic techniques used and the basic physics underlying superfluid He-3. We then describe in more detail vibrating wire techniques which are used for all the turbulence experiments ill the low temperature limit. Finally we discuss the low temperature superfluid He-3 experiments which have been made to date and compare the findings with observations in superfluid He-4 and with the ideas of classical turbulence.