Simulation of flashover generated by strong tem-wave in MITL with inner coaxial dielectric insert

Extremely sharp rise time of high-power relativistic electron beam was achieved by using of the long dielectric insert build into the cathode line of the magnetically insulated transmission line (MITL)¹. Presented paper is devoted to a theoretical treatment of this process. Efficiency of the sharp front formation grows owing to its dependence on the speed of the flashover front propagation. So, an estimation of this dependence is a step of great importance in solution of the problem. To do this, the problem of TEM - wave diffraction on the coaxial line and dielectric insert conjunction has been solved rigorously. It allows the electric field to be found at any time moment and at any point of dielectric. The flashover front speed has been estimated on physical grounds which can be derived from experimental data for the early phase of dielectric surface flashover in vacuum.