Eddy currents from moving point sources of magnetic field in the Gravity Probe B experiment

Two boundary-value problems in plane geometry, modeling the field and current distribution produced by moving sources of magnetic field (fluxons) in surrounding normal metals, are solved analytically. In the first case a fluxon moves with a constant velocity in a superconducting plane separated by a vacuum gap from a half space filled with a metal having a low electrical conductivity. Tn the second case the half space is replaced by a thin metal layer of high conductivity. The problems are solved by perturbation techniques, the Fourier integral transform, and the Parseval identity. The latter is used to calculate the power dissipated in the metal. An estimate of the power dissipation is needed in order to calculate certain torques of magnetic origin in the Gravity Probe B project. (C) 1998 American Institute of Physics. [S1063-7842(98)00102-0].