Modeling Of Powerful Microwave Pulse Propagation In Air Breakdown Environment

A high power microwave pulse can cause breakdown of the background gas and produce a space-time dependent plasma. The plasma electrons will then attenuate the tail portion of the pulse through collisional absorption. This is so called 'tail erosion' phenomenon. If the electron density reaches the cutoff density of the microwave pulse, the cutoff reflection will cause even serious tail erosion and severely limit the transmission of the pulse energy. Experiments ^1,2 have been conducted to examine the tail erosion phenomenon by transmitting microwave pulses (1.1 μs, and hundreds of KW power level) through a large plexiglas chamber filled with dry air at 1 to 2 torr pressure. The dependence of the characteristic features of tail erosion of the transmitted pulse on their initial amplitudes is determined and used for validating the proposed theoretical model.