Observation of quantum turbulence in superfluid 3He-B using reflection and transmission of ballistic thermal excitations

Jackson, Martin and Bradley, David Ian and Guénault, Anthony Michael and Haley, Richard Peter and Pickett, George Richard and Tsepelin, Viktor (2017) Observation of quantum turbulence in superfluid 3He-B using reflection and transmission of ballistic thermal excitations. Physical review B. ISSN 1098-0121

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Abstract

We report measurements of quantum turbulence generated by a vibrating grid in superfluid $^3$He-B at zero pressure in the zero temperature limit. Superfluid flow around individual vortex lines Andreev-reflects incoming thermal ballistic quasiparticle excitations, and allows non-invasive detection of quantum vortices in $^3$He-B. We have compared two Andreev reflection-based techniques traditionally used to detect quantum turbulence in the ballistic regime: quasiparticle transmission through and reflection from ballistic vortex rings and a turbulent tangle. We have shown that the two methods are in very good agreement and thus complement each other. Our measurements reveal that vortex rings and a tangle generated by a vibrating grid have a much larger spatial extent than previously realised. Furthermore, we find that a vortex tangle can either pass through an obstacle made from a mesh or diffuse around it. The measured dependence of vortex signal as a function of the distance from the vibrating grid is consistent with a power-law behaviour in contrast to turbulence generated by a vibrating wire which is described by an exponential function.

Item Type:
Journal Article
Journal or Publication Title:
Physical review B
ID Code:
84967
Deposited By:
Deposited On:
01 Mar 2017 14:00
Refereed?:
Yes
Published?:
Published
Last Modified:
22 Sep 2020 03:11