Simulation of intense microwave pulse propagation in air breakdown environment

Summary form only given. When a high-power microwave pulse propagates in air with a breakdown threshold below the wave field of the pulse, the ionization of the air will occur. The electrons produced will attenuate the field amplitude at the tail portion of the pulse. If the electron density reaches the cutoff density of the microwave pulse, the reflection caused by cutoff will even cause severe tail erosion. An experiment was conducted to examine the phenomena. In the experiment, a 1-MW microwave pulse (1.1 μs) was propagated through a large Plexiglas chamber filled with dry air at low pressure at one side of the chamber, and was received and monitored at the other side. Two different degrees of tail erosion caused by two different mechanisms were identified experimentally. A computer simulation of the experiment was then carried out. Two coupled partial differential equations (PDEs) were used to describe the intense microwave pulse propagating in the air breakdown environment. A software package developed to solve PDEs was used to solve the equations with boundary conditions satisfying the experimental situation. Calculations of the pulse intensity and electron density as a function of space and time were compared with data, with good agreement