Currents Induced in the Human Body for Exposure to Ultrawideband Electromagnetic Pulses

We have used the recently developed frequency-dependent finite- difference time-domain FD 2TD method to calculate internal electric fields and induced current densities in a 1.31-cm resolution anatomically based model of the human body for exposure to an ultrawideband vertically polarized electromagnetic pulse EMP. The Fourier spectrum of the pulse revealed that it had energy content to about 1500 MHz with the bulk of the energy being in the frequency band 400-800 MHz. The complex permittivities ew for the various tissues are known to vary a great deal over the wide bandwidth of the incident pulse. In the FD 2 TD formulation, these frequency-dependent ew have been described by the best-fit two-relaxation Debye equations with different constants for the sixteen tissues fat, muscle, blood, etc. that are used in defining the anatomically based model. From the values of the induced electric displacement vector D, we have calculated the time variations of the vertical currents that pass through each of the sections of the model that is assumed to be either isolated or shoe-wearing, standing above a perfectly conducting ground plane. Peak vertical currents with magnitudes on the order of 1-4 mA per Vm of incident electric fields are calculated with the highest values calculated for the sections through the bladder and slightly above it.... Ultrawideband pulse exposure, Anatomically based model, Dispersive properties of various tissues, Induced fields and currents.