|project title:||Hydrodynamics of 3He|
|project leader:||Dr. Ladislav Skrbek , Mr. Timofiy Chagovets and Mr. David Schmoranzer|
|access given (in days):||122|
|access used (in days):||128|
|local host:||Prof. Matti Krusius|
|home institution:||Institute of Physics ASCR, Dept. of Low Temperature Physics|
|country of institution:||Czech Republic|
|starting date (yyyy-mm-dd):||2005-01-01|
Prof. Ladislav Skrbek is a researcher from the Joint Low Temperature Laboratory of the Academy of Sciences of the Czech Republic and a professor of the Charles University in Prague. He is an expert on superfluid hydrodynamics and turbulence in superfluid 4He. The main goal in this work is to understand the coupled two fluid hydrodynamics when both the superfluid and normal components are in turbulent flow. The purpose with the visits to the Low Temperature Laboratory is to establish a comparison to superfluid 3He-B where the normal component is so viscous that it remains in laminar flow in any practical experimental setup even if the superfluid component is turbulent. In this case the dynamics simplifies to that of the superfluid component only. In addition, measurements of different type and information content can be performed in 3He-B than in the more conventional superfluid 4He.
The collaboration with Prof. Skrbek and his graduate students experienced a major step forward during the three-month period 3 April - 24 June, 2006, when Timofey Chagovets joined the work in the Low Temperature Laboratory. Measurements were then conducted with commercial quartz tuning fork oscillators, which are in general use as frequency standards in watches. The question of interest was whether they can be employed as sensors for vortices in superfluids. This possibility arose during recent measurements where these devices were studied and calibrated for thermometry both in 3He and 4He liquids in Helsinki, Prague, and Kosice. Studies on vortex detection with quartz tuning fork oscillators have been continued since then here in the Low Temperature Laboratory in rotating flow of 3He-B, in prof. Skrbek's laboratory in thermal counterflow of superfluid 4He, and by prof. Peter Skyba's group in Kosice in a quiescent bath of 3He-B. This collaboration and its continuation were discussed at a User's Meeting end of March, 2008. There exists clearly a great need for new sensors for vortex measurements in both superfluids and the decision was formed to continue the joint work. Reports: R. de Graaf, R.E. Solntsev, T.V. Chagovets, V .B. Eltsov, R. Hanninen, and M. Krusius, The dynamics of vortex generation in superfluid 3He-B, arXiv:0708.3003v1 [cond-mat.stat-mech], to be submitted to Phys. Rev. B. Blazkova, M., Clovecko, M., Eltsov, V.B., Gazo, E., de Graaf, R., Hosio, J.J., Krusius, M., Schmoranzer, D., Schoepe, W., Skrbek, L., Skyba, P., Solntsev, R.E., and Vinen, W.F., Vibrating quartz fork - a tool for cryogenic helium, Journal of Low Temperature Physics, 150, p. 525-535 (2008).