Methods of Calculating Forces on Rigid Magnetic Media
arXiv:physics/0312027
Abstract
Despite 180 years of theory on magnetism, it appears that the practice of calculating forces on magnetic media is ambiguous, as illustrated by a recent article by Casperson. Potentially troubling issues include: Which field B or H should be used? Should the total field be used, or only the external field? And if the latter, what is meant by "external"? Can/should effects of magnetization currents and/or fictitious magnetic poles be included? What is the force on only a portion of a circuit? We review several well-known approaches to magnetic force calculations on elements of rigid circuits, and find it very helpful to use an explicit example to compare and contrast the various methods.
7 pages, no figures