Development of MAGY code for modeling of coaxial Gyrotrons

Summary form only given. MAGY (Maryland Gyrotron) code is a highly efficient code designed to simulate fast wave vacuum electronic devices, such as gyrotrons, gyro-klystrons, gyro frequency multipliers. The model includes a self-consistent, nonlinear solution of the three-dimensional electron equations of motion and the solution of time-dependent field equations. The model differs from the conventional Particle in Cell approach in that the field spectrum is assumed to consist of a carrier frequency and its harmonics with slowly varying envelopes. In particular, the code can treat an arbitrary set of temporal and cyclotron harmonics. Other features include treatments of losses due to the presence of absorbing materials, a realistic profile of guiding magnetic field, and azimuthal inhomogeneity of the electron beam with a local velocity spread. Examples of MAGY usage include NRL/CPI gyro klystrons, UMD frequency multipliers, mode competition in gyrotrons for fusion, and parametric mode coupling due to non-homogeneity of electron beam. MAGY simulations demonstrate good agreement with experimental measurements and with known analytical calculations. Coaxial gyrotrons have superior mode selectivity with respect to gyrotrons with cylindrical cavities, but their design requires extensive computational effort to optimize their complex coaxial structure. Thus, new computer codes are required for successful design of coaxial gyrotrons. Development of MAGY code to allow simulations of coaxial gyrotrons is one step in this direction.