MSC Seminar. 18/11/2024. Marlone Vernet (MSC, UPC): “Experimental study of the thermoelectric effect at a liquid metal interface”

The Seebeck effect refers to the conversion of heat into electricity, typically achieved by thermoelectric devices using solid electrical conductors or semiconductors. This principle has been widely exploited in industrial applications such as thermocouples but few studies have looked at this effect in liquid metal systems. Although the possible implications range from the cooling blanket of tokamaks to the magnetic field of certain planets, experimental data on this interaction are scarce. In this study, we present the first experimental evidence of the Seebeck effect occurring at the interface between two liquid metals at room temperature, namely gallium and mercury. The liquid nature of this interface significantly affects the conventional temperature distribution, resulting in an abnormally high current density near the boundaries. Upon a uniform vertical magnetic field, the thermoelectric currents generate a Lorentz force that leads to effective thermoelectric fluid pumping. This effect could hold substantial relevance in a variety of industrial and astrophysical contexts, including the promising development of liquid-metal batteries and the dynamics of Jupiter’s magnetic field.