Further comments on reciprocity integral for magnetic recording

A straightforward and physically motivated derivation of the reciprocity integral in magnetic recording theory is given for the quasi-static limit, where electromagnetic radiation and retardation effects are neglected, but frequency dispersion in the read head from all sources, including eddy currents, is specifically accounted for. This work attempts to correct some errors or misconception on this subject matter that remain in the literature. Index Terms - Flux linkage, frequency dispersion, high frequency read head, reciprocity integral, reciprocity principle.