CONVECTIVE TEMPERATURE-FLUCTUATIONS IN LIQUID GALLIUM IN DEPENDENCE ON STATIC AND ROTATING MAGNETIC-FIELDS

The influence of static axial, static transversal, and rotating magnet ic fields on convective temperature fluctuations in liquid gallium (te mperature range around 800 degrees C, Prandtl number 2.5 . 10(-3)) has been investigated. For a Rayleigh number of 6.3 . 10(5) (Delta T = 10 degrees C, h = 50 mm), convective temperature fluctuations with peak to peak values of 3 degrees C have been measured. Depending on the str ength, the frequency, and the configuration of the field, they could b e eliminated to Delta T < 0.01 degrees C (static axial field of 182 mT ), damped to a nearly periodic state with 0.1 degrees C amplitudes (st atic transversal field of 45 mT), or reduced to 0.03 degrees C oscilla tions by applying a rotating field.