Temperature fluctuations of the Marangoni flow in a liquid bridge of molten silicon under microgravity on board the TR-IA-4 rocket

Temperature fluctuation measurements in a liquid bridge of molten silicon, which shows the Marangoni flow in highly super-critical condition, are performed in a half-zone configuration under microgravity on board a TR-IA-4 rocket and on the ground. In the microgravity experiment, two types of temperature oscillation are observed during the melting process of silicon and in the cylindrical half-zone melt. The former oscillation, which has a frequency of about 0.1 Hz during the melting process, has an antiphase correlation of temperature oscillation measured in thermocouples separated by 90° azimuthal angles. The latter oscillation in the cylindrical liquid bridge has no remarkable frequency; however, it tends to have the antiphase correlation in between thermocouples with 180° azimuthal angles. In the ground experiment, temperature fluctuations have a characteristic frequency of 0.2 Hz and there is an antiphase correlation of temperatures in thermocouples with 180° azimuthal angles by using the slender melt zone.