# Possible Visualization of a Superfluid Vortex Loop Attached to an Oscillating Beam

Authors
• 1 Centro Atómico Bariloche, CNEA, Inst. Balseiro UNC, CONICET, San Carlos de Bariloche, 8400, Argentina , San Carlos de Bariloche (Argentina)
• 2 Osaka City University, Department of Physics, Osaka, 558-8585, Japan , Osaka (Japan)
Type
Published Article
Journal
Journal of Low Temperature Physics
Publisher
Springer US
Publication Date
Feb 24, 2015
Volume
179
Issue
5-6
Pages
310–319
Identifiers
DOI: 10.1007/s10909-015-1282-1
Source
Springer Nature
Keywords
Visualization using tracer particles is a relatively new tool available for the study of superfluid turbulence and flow, which is applied here to oscillating objects submerged in the liquid. We report observations of a structure seen in videos taken from outside a cryostat filled with superfluid helium at 2 K, which is possibly a vortex loop attached to an oscillator. The feature, which has the shape of an incomplete arch, is visualized due to the presence of solid H2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm{H}_2$$\end{document} tracer particles and is attached to a beam oscillating at 38 Hz in the liquid. It has been recorded in videos taken at 240 frames per second, fast enough to take ∼6\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\sim }6$$\end{document} images per period. This makes it possible to follow the structure, and to see that it is not rigid. It moves with respect to the oscillator, and its displacement is in phase with the velocity of the moving beam. Analyzing the motion, we come to the conclusion that we may be observing a superfluid vortex attached to the beam and decorated by the hydrogen particles. An alternative model, considering a solid hydrogen filament, has also been analyzed, but the observed phase between the movement of the beam and the filamentary structure is better explained by the superfluid vortex hypothesis.