Аннотация:The understanding of the phase transitions at the surface of a growing crystal is mainly based on the data on ice crystals transformations. The relations of the growth rates and crystal habits to temperature and water vapor saturation in surrounding for ice are well established and are widely used. However, the processes of ice--vapor phase transitions in a multielement ice crystal system, such as natural snow, are of great importance for the macro scale ``effective'' physical properties of snow. They regulate the chemical and isotopic transformations at the ice matrix surface, are not well understood and show considerable differences from those reported from single crystals studies. We present the experimental results on snow structure evolution caused by an externally-applied heat flow and observed by computed microtomography. The 3D reconstructions of the recrystallizing snow in non-disturbed snow samples were made with high temporal resolution simultaneously with measuring the effective thermal conductivity of snow. The process of structural change was slowing down with time up to achieving a certain equilibrium with the heat and mass transfer through the snow samples. The meaning of this "equilibrium stage" for the recrystallization in multielement systems will be discussed.
http://flux.aps.org/meetings/YR04/MAR04/baps/abs/S7810002.html