Features of the He II film transfer effect in the presence of an alternating electric field
Abstract
The effect of an alternating electric field on the He II film transfer effect is detected and studied. The investigations are carried out in the temperature range from 1.5°K to Tλ for field strengths of 1.105 to 2.105 V/cm and frequencies of f = 0−1000 Hz. It is determined that in the presence of an alternating electric field the helium film transfer velocity is significantly reduced up to its complete cessation. We completely control and reproduce the effect, and the amount of it grows for an increase of field strength and film height (decrease of level difference). The effect varies nonmonotonically with frequency change: the maximum effect of the field takes place for moderate frequencies (20 to 50 Hz), practically disappearing for f = 1000 Hz and f = 0 (dc field). A temperature rise will lead to a slight decrease of the effect, which completely disappears for transition through Tλ. The observed phenomena are explained by a model of excitation of film thickness oscillations.