Analysis of bulk radiative heat transfer in a crystal and in a melt using numerical simulation of the sapphire crystal growth by the Stepanov method

The effect of bulk radiative heat transfer during the growth of profiled sapphire crystals from the melt is studied by the numerical simulation method. The peculiarities in the structure of a lightguide flow in the crystal and in the melt, as well as the possibility of radiation instability of the interface, are considered. It is shown that overcooled regions with the size determined by the growth rate appear under the crystallization front. It is found that the use of a conical shaper ensures a more stable growth.