Published by the Institute of Electrical and Electronics Engineers for the Magnetics Group
IEEE Transactions on Magnetics vol:44 issue:6 pages:710-713
The linearization of an electromagnetic formulation by the Newton method can be expressed similarly as for the linear case, by introducing
differential material matrices. For the case of the finite-integration technique applied to an orthogonal grid, the chord material
matrix is diagonal whereas the differential material matrices includes off-diagonal bands, representing the cross-directional coupling introduced
by the nonlinearity. An approximative Newton method based on a unidirectional differential material matrix yields a diagonal
matrix, which has a higher computational efficiency but may lead to a degenerated convergence.