Transient magnetic field formulation for solid source conductors with axial symmetry

The simulation of transient magnetic field problems requires the repeated and successive solution of high-dimensional linear systems with near-identical system matrices and different righthand side vectors. The combination of conjugate gradient method with subspace projection methods is shown. Additionally, the formulation for the azimuthal component of the magnetic vector potential for axisymmetric magnetostatic applications reveal a singularity which is the source of numerical instability. A variable transformation is introduced to remove the singularity from the numerical scheme and to move it to the postprocessing.