Numerical study of the propagation of high power microwave pulse in air breakdown environment

A high power microwave pulse can cause breakdown of the background gas and produce a space-time dependent plasma. A theoretical model describing the propagation of an intense microwave pulse in air breakdown environment including Poynting's equation for the continuity of the power flux of the pulse and the rate equation of the electron density. A transformation to the frame of local time of the pulse is introduced to separate the spatial and temporal derivatives in the two modal equations. Thus, the required computation time can be reduced considerably and ODE subroutine for numerical analysis is well established. A comprehensive numerical analysis of the propagation of the intense microwave pulse through the atmosphere is performed. It is shown that the pulse energy can severely be attenuated by the self-generated plasma. The parameters of the pulse including the pulse power, carrier frequency and the pulse length are then varied to determine the conditions for minimizing the energy loss of the pulse before reaching the destination. An empirical formula relating these parameters of the pulse is then deduced from these conditions for practical applications. The case of achieving a maximum ionization at a destined region in the upper atmosphere will be presented as an application of the model