QFS2016 Book of Abstracts

Abstracts

P2.11 Working parameters of a Paul Trap to study charged bubbles in liquid helium Joseph Emil Mathew(1), Vadakkumbatt Vaisakh(2), Ghosh Ambarish(1,2) 1) Indian Institute of Science, Centre for Nano Science and Engineering, Bangalore, India, 560012. 2) Indian Institute of Science, Department of Physics, Bangalore, India, 560012. In a recent experiment, we have used a linear Paul trap to hold and study multi-electron bubbles (MEBs) in liquid helium. MEBs have a charge-to-mass ratio (between 10 − 4 to 10 − 2 C/kg) which is several orders of magnitude smaller than ions (between 10 6 to 10 8 C/kg) typically studied in traditional ion traps. In addition, MEBs experience significant drag force while moving through the liquid. As a result, the experimental parameters, such as applied voltages and electric field frequencies, for stable trapping of MEBs are very different from those used in traditional ion trap experiments. The purpose of this paper is to model the motion of MEBs inside a linear Paul trap in liquid helium, determine the range of working parameters of the trap, and compare the results with experiments. P2.12 The Flow Resistance of the Oscillating Tuning Fork Immersed in Superfluid Helium Gritsenko I., Klokol K., Tseskis A., and Sheshin G. B.Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Kharkiv, Ukraine The result on the motion of He II excited by a tuning fork are analyzed. It is shown that before attaining certain threshold values by a parameter, with the structure of the Reynolds number, the normal and superfluid components move independently. In this case the force and the drag coefficient are completely determined by the motion of the normal component. When the parameter exceeds the threshold value which is critical for velocity the turbulent flow regime begins to work. This regime at a temperature below that for the transition to a superfluid state is attributed to the formation of quantized vortices. The motion of helium at a temperature above the transition point is discussed.

60