Magnetohydrodynamic Effects of a Gradient Magnetic Field on Liquid Metal Flows

The liquid metal divertor approach shows promise for being able to withstand high heat and particle fluxes using a self healing surface, and is an alternative to the traditional solid divertor. Liquid metals have beneficial properties such as high thermal and electrical conductivities, which are necessary for efficient heat removal. We aim to improve the understanding of the effect of magnetic gradient field on liquid metal channel flow and explain magnetohydrodynamic (MHD) phenomena. Current considerations include the MHD drag opposing liquid motion, induced electrical currents, Lorentz force, and understanding the velocity distribution. The change in magnetic field with time has shown a liquid jump, but in a tokamak where the toroidal magnetic field is steady state, the change in magnetic field with position needs to be addressed. Experimental and numerical results are presented on the magnetic field gradient, with experiments performed at the LMX-U facility at PPPL.