Mutual-friction induced instability of normal-fluid vortex tubes in superfluid helium-4

Kivotides, Demosthenes (2018) Mutual-friction induced instability of normal-fluid vortex tubes in superfluid helium-4. Physics Letters A, 382 (22). pp. 1481-1485. ISSN 0375-9601 (https://doi.org/10.1016/j.physleta.2018.03.051)

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Abstract

It is shown that, as a result of its interactions with superfluid vorticity, a normal-fluid vortex tube in helium-4 becomes unstable and disintegrates. The superfluid vorticity acquires only a small (few percents of normal-fluid tube strength) polarization, whilst expanding in a front-like manner in the intervortex space of the normal-fluid, forming a dense, unstructured tangle in the process. The accompanied energy spectra scalings offer a structural explanation of analogous scalings in fully developed finite-temperature superfluid turbulence. A macroscopic mutual-friction model incorporating these findings is proposed.