Origins of convective temperature oscillations in crystal growth melts

Abstract

Sinusoidal temperature oscillations of large amplitude and with periods ranging from a few seconds to a few minutes have been reported for many different crystal growth melt materials and configurations. In this paper, several models of the origins of these temperature oscillations are described which successfully explain the results reported for various materials. At low values of the Rayleigh number, the instability of the convection roll itself in the form of transverse waves is the primary source of temperature oscillations. At higher values of the Rayleigh number, periodic boundary layer instabilities develop in thermal layers for high Prandtl number fluids (such as molten oxides) and momentum layers for low Prandtl number fluids (such as molten metals and semiconductors).