Low Temperature Physics: 44, 1062 (2018); https://doi.org/10.1063/1.5055848
Fizika Nizkikh Temperatur: Volume 44, Number 10 (October 2018), p. 1353-1357    ( to contents , go back )

Some features of the long-pulse regime of propagation of a phonon sheet in superfluid 4He

R.V. Vovk

V.N. Karazin Kharkiv National University, Kharkiv 61077, Ukraine
E-mail: rvvovk2017@gmail.com

C.D.H. Williams, and A.F.G. Wyatt

School of Physics, University of Exeter, Exeter EX4 4QL, United Kingdom
pos Анотація:

Received March 13, 2018, published online August 28, 2018

Abstract

The angular distributing of energy density of “phonon sheet” at it propagation in superfluid 4He at length of impulse about 300 ns is investigated. The availability of flat top on angular dependences of phonon signal is explained by formation of «hot» area in the central region of sheet and process of creation of high energy phonons in this area. The saturation of the width of the flat top for impulse near-by 300 ns is explained by realization of the long pulse regime.

Key words: superfluid helium, phonon penetration, phonon bean, heat pulses.

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