The Kinetics of the Anomalous State Formation and the Growth of Helium Crystals at High Supersaturation

摘要

The kinetics of the formation of an anomalous state of a helium crystal with a fast-growing surface are investigated. It is demonstrated experimentally that it is external supersaturation that is the determining factor of formation of an anomalous state. The dependence of the time of formation of anomalous state on temperature and initial supersaturation is measured. the problem of crystal growth with the excitation of the first-sound wave in the container is solved. This solution is used to determine the dependence of the kinetic coefficient of growth of anomalous facets on temperature and initial supersaturation. It is demonstrated that the kinetic coefficient of facet growth decreases on approaching the boundaries of the region of the existence of an anomalous state. The kinetic coefficient of growth of atomically rough surfaces in an anomalous state is determined by the damping of pressure oscillation. It is found that the value of the latter coefficient is three-four times that of the respective value for the facets but is considerably, by an order of magnitude, less than the value of the coefficient of growth of such surfaces in the normal state. Phenomena are treated which accompany the spiral growth of facets, namely, the excitation of oscillations of a screw dislocation during spiral rotation and the emergence of vortex rings in superfluid helium. The effect of these phenomena on the kinetics of facet growth and on the formation of an anomalous state is discussed.