On the significance of polarization charge and isomagnetic surface in the interaction between conducting fluid and magnetic field

摘要

From the frozen-in field lines concept, a highly conducting fluid can movefreely along, but not traverse to, magnetic field lines. We discuss this topicand find that in the study of the frozen-in field lines concept, the effects ofinductive and capacitive reactance have been omitted. When admitted, therelationships among the motional electromotive field, the induced electricfield, the eddy electric current, and the magnetic field becomes clearer andthe frozen-in field line concept can be reconsidered. We emphasize theimportance of isomagnetic surfaces and polarization charges, and showanalytically that whether a conducting fluid can freely traverse magnetic fieldlines or not depends solely on the magnetic gradient in the direction of fluidmotion. If a fluid does not change its density distribution and shape (can beregarded as a quasi-rigid body), and as long as it is moving along anisomagnetic surface, it can freely traverse magnetic field lines without anymagnetic resistance no matter how strong the magnetic field is. When ouranalysis is applied, the origin of the magnetic field of sunspots can beinterpreted easily. In addition, we also present experimental results tosupport our analysis.