Abstract
Solid 4He is grown in the superfluid, and its growth rate becomes enormously high at low temperature. The equilibrium crystal shape is sensitive to the gravity due to this enormously fast growth rate. The true crystal shape should be studied under the microgravity environment. The present study is the basic research aimed at the experiment in the space. The main result presented here is a new finding of the very fast growth rate ofc-facet driven by the acoustic wave and observed with the fast video camera. The new mechanism of the facet growth is presented to explain the experimental result. Some possible experiments with respect to the crystal shape of 4He are also presented to be performed on the jetplane.
