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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.
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