Electromagnetic confinement, centering, guiding of a liquid-metal jet

This study illustrates how to suppress the walls usually necessary to center and to guide a molten metal flow or to maintain the circular shape of its section, by substituting for them the action of high frequency magnetic fields. Some intuitive considerations about the effects induced in a liquid metal by such fields lead to the use of the configuration of a rotating quadrupole field to achieve the desired functions. A theoretical justification is given on the basis of the analysis of the pressure and velocity fields generated by quadrupole fields rotating in a continuous or in a reversible way.