ABSTRACT
Although both HEMP and lightning are threats to aircraft in flight, differences between them occur on several distinct levels of the interaction process. This chapter describes the electromagnetic environments generated by high altitude electromagnetic environments (HEMP) and lightning. For HEMP, this environment is characterized by the waveform of a plane wave incident on the aircraft and its Fourier transform. It presents the simple geometric and physical models used to characterize the salient features of the interaction of the currents and fields with the aircraft and compares natural lightning and HEMP on the surface of the aircraft. In a comparison of HEMP and lightning, high frequency signals affecting system electronics should also be considered. The total energy content delivered to an aircraft by a lightning direct strike is larger than that delivered by HEMP. During the first microsecond of HEMP generation, the weapon prompt gamma rays Compton scatter electrons from air molecules that are then bent by the earth's magnetic field.
