Experimental Observation and Theoretic Analysis MHD Effects of a Liquid Metal Jet in a Gradient Magnetic Field

The advanced limiter-divertor plasma-facing system (ALPS) has been studied for several years, but the magnetohydrodynamic (MHD) stability of free surface jet flow in a gradient transverse magnetic field is one of the key remaining issues. Recently, some experiments on jet flow were performed with a 0.2- to 1.95-T gradient magnetic field and 2.9, 3.24, and 4.10 m/s velocities for a flow diameter of 6 mm. The results indicated that the transverse gradient magnetic field strongly shortens the jet flow range and the shape of the cross section of the jet flow deforms from round to elliptical and finally becomes a bowed-down shape in the jet flow downstream under these experimental conditions. This paper includes simple modeling of jet flow MHD stability in a gradient transverse magnetic field, which derives the velocity and the area of the cross section of the jet flow along the flow path. The theoretical expected values are in good agreement with experimental results.