Experiments on the oscillatory convection of low Prandtl number liquid in Czochralski crystal growth under an axial magnetic field

Abstract

Experimental results are presented on the oscillatory convection of mercury in a Czochralski configuration under an imposed axial magnetic field. A thermal wave propagating in an azimuthal direction under the axial magnetic field of moderate strengths is generated which proves the existence of azimuthal swirl flow in the oscillatory natural convection. In the presence of rotating flow by a Crystal-model disk rotation, axial magnetic field can also generate a long-period thermal wave and can amplify the temperature fluctuation depending on the magnitude of the relevant flow similarity parameters. A flow regime diagram is presented for the amplification and damping of the temperature fluctuation under an axial magnetic field in order to provide a data base for finding optimum growing conditions in a Czochralski process using axial magnetic field.