THE LORENTZ FORCES ON AN ELECTRICALLY CONDUCTING SPHERE IN AN ALTERNATING MAGNETIC-FIELD

A method to calculate the Lorentz force on an electrically conducting sphere placed in an arbitrary sinusoidally varying magnetic field is d eveloped. The crux of this method lies in expressing the external magn etic field and the eddy current density in the sphere in terms of a '' source function'' of the current sources and a ''skin depth dependent function.'' The general formula for the Lorentz force is used to deriv e the special case of a sphere in an axisymmetric stack of circular cu rrent loops, Numerical results for this case are presented as a functi on of the stack geometry. Approximations of the skin depth functions f or practical situations are presented. Finally, a procedure to determi ne the magnetic pressure distribution on the surface of a levitated li quid metal droplet is given.