Two-dimensional calculation of nonsequential electron layer generation by crossed microwave beams in low-pressure air

Summary form only given. A pulse envelope formulation for computationally modeling electron layer generation in laboratory chamber experiments in low-pressure (0.1-10-torr) air irradiated with long-pulse (100-600-ns), 2.856-GHz crossed microwave beams has been previously described (see D.J. Mayhall et al., 1989). A second calculation has been done for a linearly rising incident pulse, which reaches a plateau of 0.159 MV/m at 80 ns. In this case, five layers also occur, but their character and timing are much more like those of the experimental layers than are those in the first calculation. These layers form from a number of coalescing blobs. Flutes form on both sides of the first layer. Blobs in the first and second layers coalesce. The second and third layers consist of isolated blobs. The calculated appearance times vary from the experimental by 6% to 26%. When the plateau value of the incident pulse is reduced by 30% to 0.111 MV/m at 80 ns, the appearance times vary from 70.6 to 84.9 ns and differ from the experimental by 5-20%. This calculation thus gives the best agreement with experimentally observed appearance times