The Eroding Foil Switch (EFS) model

An analysis of the results of two experiments, the Los Alamos Foil Switch Experiment and the Magnetic Gate Experiment, reveals evidence of mass loss and unexpectedly high temperatures in strongly accelerated aluminum foils. Nonlinear magnetic diffusion theory is analyzed both analytically and numerically and found to give strong concentrations of current density, in a propagating front, for foils thicker than a classical skin depth. This concentrated current front is found to lead to mass erosion and high temperatures in foils undergoing strong acceleration. These results are used to formulate a new model of foil kinematics called the EFS model that features both a rocket (or mass loss) phase, and a snowplow (shock wave) phase after foil disassembly. This model is shown to give good agreement with experimental results.