The flow of quantized vortex lines in superfluid 3He-B is laminar at high temperatures, but below 0.6 Tc turbulence becomes possible, owing to the rapidly decreasing mutual friction damping. In the turbulent regime a vortex evolving in applied flow may become unstable, create new vortices, and start turbulence. We monitor this single-vortex instability with NMR techniques in a rotating cylinder. Close to the onset temperature of turbulence, an oscillating component in NMR absorption has been observed, while the instability generates new vortices at a low rate ~ 1 vortex/s, before turbulence sets in. By comparison to numerical calculations, we associate the oscillations with spiral vortex motion, when evolving vortices expand to rectilinear lines.
@article{arxiv.cond-mat/0701647,
title = {Precessing vortex motion and instability in a rotating column of superfluid 3He-B},
author = {R. Hanninen and V. B. Eltsov and A. P. Finne and R. de Graaf and J. Kopu and M. Krusius and R. E. Solntsev},
journal= {arXiv preprint arXiv:cond-mat/0701647},
year = {2011}
}
Comments
revised version: 7.3 pages, 9 figures submitted to Phys. Rev. B