Nonstationary thermoelectric effect in He II and the effect on it of the transition from the laminar to turbulent regime of thermal vibrations

The observation of a nonstationary thermoelectric effect — a spontaneous electric polarization of a cell with liquid He II under thermal excitation of standing waves of a second sound in it — was confirmed (Fiz. Nizk. Temp. З0, 1321 (2004)). In the temperature range 1.4 K 0(Т) was registered: in the region w 0, the potential oscillations are regular and their amplitude increases in proportion to the power; when w > w0, the electrical response acquires a random character with an increase in fluctuations and an amplitude decreasing to zero, a kind of electromagnetic noise is observed. The results of the experiments are compared with the conclusions of the theory of flexoelectric polarization of liquid helium. The polarization of liquid helium upon the excitation of the first sound waves and the shock waves of pressure and temperature is also discussed. © 2020 Institute for Low Temperature Physics and Engineering. All rights reserved.