Victor B. Efimov

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Rogue waves have been observed in superfluid helium. The experimental system consists of high intensity second sound (temperature-entropy) waves within a resonant cavity. Under steady state conditions, with a constant oscillatory driving force at the resonant frequency, the waves are turbulent and there are fluxes of energy towards both high and low(More)
Permeability of cell envelope of Escherichia coli was investigated by the method of osmotic shock for thiourea, dimethylsulfoxide and glycerol. Characteristic times were obtained for passive permeation of these reagents. Variation of r in consequence dimethylsulfoxide less than thiourea less than glycerol was determined. The dependence of tau on the(More)
The dynamics of an electrically-driven 8 kHz quartz tuning fork has been studied experimentally in liquid helium-4 in the temperature range 1.3< T < 4.2K under the saturated vapour pressure. The fork has relatively large dimensions compared to standard 32 kHz fork used in recent investigations. The velocity of the tip of the fork prong is measured by the(More)
We report the results of investigations of acoustic turbulence in a system of nonlinear second sound waves in a high-quality resonator filled with superfluid 4He. It was observed that subharmonics of a periodic driving force applied to the system may be generated via a parametric instability. We find that application of an additional low-frequency pumping(More)
We review studies of the generation and propagation of nonlinear and shock sound waves in He II the superfluid phase of He , both under the saturated vapor pressure SVP and at elevated pressures. The evolution in shape of second and first sound waves excited by a pulsed heater has been investigated for increasing power W of the heat pulse. It has been found(More)
Deepak Garg,1 V. B. Efimov,1,2 M. Giltrow,1 P. V. E. McClintock,1 L. Skrbek,3 and W. F. Vinen4 1Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom 2Institute of Solid State Physics RAS, Chernogolovka, Moscow region, 142432 Russia 3Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Prague, Czech Republic(More)
Recent work on second sound acoustic turbulence in superfliud '̂ He is reviewed. Observations of forward and inverse energy cascades are described. The onset of the inverse cascade occurs above a critical driving energy and it is accompanied by giant waves that constitute an acoustic analogue of the rogue waves that occasionally appear on the surface of the(More)
We have investigated a copper-mesh grid oscillating at its fundamental (0,1) Bessel mode in isotopically pure superfluid He for temperatures 10 < T < 1500mK at a pressure of P = 5 bar. The high quality factor (Q ∼ 10) of the oscillator allowed us to observe new features of its response to a periodic drive which, at the lowest T , was found to depend on the(More)
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