Time-domain numerical simulation of EM pulse propagation through a time-varying slab

Problems involving time-varying parameters are of interest for the purpose of investigation of electromagnetic wave propagation in the ionosphere, for remote sensing of unstable objects by short electromagnetic pulses, etc. A necessity of considering such problems stems also from the investigation of ultrafast electromagnetic phenomena in semiconductor and quantum electronics. For the problem solving in the differential statement, the FDTD method has gained wide recognition. An alternative approach reduces the problem to a perturbation method or integral equations. Using a resolvent method for solving the obtained Volterra integral equations that characterise electromagnetic transients enables us to formulate the evolutionary recursion method. A direct numerical time-domain integral equation method is extended to the case of a dissipative dielectric whose permittivity and conductivity change arbitrarily in time