Calculation of high altitude nuclear electromagnetic pulse propagation in ionosphere

Additional current density, which is a function of frequency, can be used to describe the effect of the ionosphere in the process of electromagnetic pulse propagation. In time domain, however, this effect can be expressed in two terms: current density and conductivity. Their time-domain expressions were derived in differential equation forms, which are the functions of ionosphere parameters and the electric field exerted. These current and conductivity were used directly in the high altitude nuclear electromagnetic pulse (HEMP) calculations, for which these computations need to be held in time domain to simulate the HEMP stimulation and propagation in the ionosphere simultaneously. As an example, three cases of the stimulation and propagation of HEMP exploded at a height of 100 km were cal