Investigating the stability of solid and liquid bodies levitating in a high-frequency electromagnetic field 1. Numerical Results

Yu. M. Gelfgat - I. Grants - Yu. Krumins - A. Mikelsons

University of Latvia, Institute of Physics, Salaspils-1, LV-2169, Latvia

Abstract
The paper discusses the stability conditions for an electrically conducting sphere (ball) levitating in an electromagnetic field induced by a high-frequency inductor and ex-posed to rotary and oscillatory disturbances. The inductor is assumed to be a circle winding AC supplied. A relative frequency w* = m0swR02 (where s and R are the elec-trical conductivity and the radius of the sphere, w is the angular frequency of the cur-rent in the inductor) is shown to be the basic criterion determining stable or unstable levitation of the sphere. It has been found out that at w* < w*c the sphere’s levitation is stable, but at w* > w*c it is unstable, yet a critical value of the relative frequency is w*c = 10 ± 2 for both types of disturbances. The numerical data agree well with the ex-perimental results. This paper describes the experiment in brief because it will be dis-cussed in detail in a separate article. Figs 4, Refs 4.