Thermocapillary convection in a liquid metal under influence of the magnetic field - experimental techniques and results of the tests

Thermocapillary convection in low-Prandtl-number fluids up to now remains insufficiently studied experimentally due to difficulties to realize free surface conditions on liquid metals. A novel technique has been developed to produce small sized easily transportable deep vacuum container filled with a thin layer of gallium under a transparent glass window. The first tests showed that the free surface of the liquid gallium did not deteriorate during a period of up to 45 days. The flow pattern on the free surface, while point heating the bottom of the container, has been demonstrated. The temperature gradient on the free surface of the liquid gallium caused surface relief deformations of an order up to 10 - 100 microns. Video recordings of the tracer particle motion on the free surface of liquid gallium due to thermal convection and surface relief deformations due to changes in heating conditions has been made. The presence of the thermocapillary convection has been demonstrated.