MHD experiments on liquid metal jet-like flows guided by curved substrates

O. Lielausis - A. A. Klyukin - E. Platacis - J. Peinbergs

Institute of Physics, University of Latvia, 32 Miera, Salaspils, LV-2169 Latvia

Abstract
In a number of forthcoming technologies, liquid metal jets have been selected for the leading role of a working medium. Strong magnetic fields are often used. The best example is the protection of the plasma facing components in fusion facilities. The stability of the jet pathway is a clear precondition for a practical success. It was stated that the passing of the jet can be effectively controlled and stabilized by means of curved substrates, either smooth or profiled. Experiments with InGaSn jets of d = 2.3 mm are described. The orthogonal to the velocity field reaches 4 T. Velocities are varied in the range 0.1 - 0.6 m/s. Essential is the influence of MHD boundary conditions, i.e. whether the wall is electrically contacting (wetted) or not. A version is described when each of the jets is directed along an apart standing curved rail. In this case, the passing of the jets remained stable over the full length of the rail, independent on whether the wall is wetted or not. It is difficult to give a clear explanation of such an intriguing behavior of the jets, in other words, of the stability of such a specific form of MHD motion. It is a base only for very general and indefinite arguments. Indications are presented that also in the case of free-flying jets the influence of an orthogonal field is in general stabilizing. It has been concluded that systems of fast liquid metal jets prevented from deviation by solid substrates could be of interest at the development of liquid metal protected divertors. Figs 6, Refs 16.