Modeling of multifrequency process in lossy structures by using MAGY

The design of vacuum electronic sources of electromagnetic radiation requires extensive computer simulations. Consequently, it is an important requirement for computer codes to be able to describe real processes occurring in these devices. The computer code MAGY developed at the University of Maryland is able to describe the self-consistent nonlinear interaction between electromagnetic fields of an axisymmetric structure and a gyrating electron beam. The code has been used successfully to simulate the operation of both gyro-amplifiers and gyro-oscillators. New applications for gyrodevices require operation at high power and high frequency in overmoded structures. Consequently, multifrequency processes including subharmonic bunching can be expected to be important. At the same time suppression of unwanted parasitic modes is critical. One of the most efficient ways to suppress parasitic modes is by lining the structure´s wall with lossy materials. This technique is widely used in vacuum microwave and millimeter wave devices. To treat this case, the computer code should be able to solve the electromagnetic field problem in the case of a partially absorbing wall. The present work was aimed to extend MAGY to analyze complex vacuum devices with finite wall conductivity operating at many frequencies.