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Suppression of Electromagnetically Induced Free‐Surface Instabilities in Liquid Metals
Author(s) -
Minchenya Vitaly,
Karcher Christian,
Chigarev Anatoly
Publication year - 2011
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.201110234
Subject(s) - lorentz force , liquid metal , magnetic field , magnetohydrodynamic drive , instability , free surface , mechanics , magnetic levitation , levitation , electromagnetic field , condensed matter physics , magnetohydrodynamics , physics , materials science , bifurcation , magnet , nonlinear system , composite material , quantum mechanics
Abstract The work presented is devoted to studies of foundations of the suppression techniques for electromagnetically induced instabilities of the free liquid metal surfaces. Such instabilities occur, for instance, in a number of technologies for requested refinement of materials like electron beam evaporation or levitation melting, in which the electromagnetic shaping technique is applied. The instability phenomenon in our case has following magnetohydrodynamic background. High‐frequency magnetic field causes Lorentz force density generation within so‐called skin‐layer in the liquid metal, which works as a surface pressure in turn. With increase of the electromagnetic pressure a destabilizing mechanism progresses within the liquid metal domain, which causes a bifurcation. In this paper we discuss application alternating magnetic fields to increase the bifurcation threshold by passive and active redistribution of the Lorentz force density in the near‐surface layers of the liquid metal domain. A novel stabilization system on the basis of a local electromagnetic influence on the liquid metal surface in the high frequency magnetic field is presented. The experimental results are discussed. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)