Experimental Investigations of Magneto-Hydrodynamic Waves

Abstract

The importance of magneto-hydrodynamic phenomena to different parts of cosmic physics is becoming more and more evident. This fact and the extreme mathematical difficulties involved in an exact treatment of many problems make it necessary to consider the possibility for experimental investigations. In this paper the fundamental equations are solved for cylindrically limited waves, a case which seems to be best adapted for experiments. It is shown that an "ideal" magneto-hydrodynamic wave in a liquid with finite conductivity can exist only in a certain frequency interval. The upper limit is set by the conductivity and the magnetic field strength. Above this value the waves degenerate into skin-waves. The lowest frequency is determined by the geometrical dimensions and by the conductivity. Waves in different liquids are compared, and liquid sodium is found to be the best medium for an experiment. A brief account is given for a preliminary experiment and other investigations are proposed.