Comparison of different methods of force calculation

Abstract

Four methods of force calculation are discussed and compared: equivalent current density, equivalent magnetic charges, the energy principle for both constant and field-dependent permeability, and Maxwell's stresses. Although the formulas for the surface force density are different, it can be shown that the same volume force density results. The reasons for different numerical results are discussed and recommendations are given to the user.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>