The field induced in a conducting sphere placed in a steady magnetic field and a perpendicular oscillatory magnetic field

摘要

The fields induced in a conducting sphere of resistivity, η, placed in a strong, steady magnetic field Ba ẑ, and a small oscillatory magnetic field (in the xy plane) of magnitude Bω have been calculated approximately for Bω/Ba ≪1 and Baeη ≪1, where n is the number density. The conducting sphere is assumed to have a uniform resistivity and number density and the ions are assumed immobile. It has been shown that: (a) If the applied oscillatory field is linearly polarized, the magnetic field induced in the conducting sphere has a rotating component for which ω is parallel to Ba ẑ. (b) If the applied oscillatory field is rotating (circularly polarized), its penetration in the conducting sphere is enhanced or impeded with respect to the classical skin effect depending on whether the sense of rotation is parallel or antiparallel to Ba ẑ. These results are consistent with the experimental observation in the rotating field plasma experiments.