PIC simulation of powerful microwave coaxial ubitron

Results of numerical simulation of a powerful coaxial UHF-ubitron are given. We received these results using the numerical 2.5-dimensional electromagnetic code, which we developed. This code is based on the PIC method. In the work the algorithm adapted to the coaxial ubitron geometry is described. The numerical analysis of ubitron operation in amplification and in generation regimes is given.