PIC code simulations on NRL gyro-amplifiers

Summary form only given, as follows. Developments on high power millimeter wave gyro-amplifiers are currently underway at NRL. Recent experiments on a folded waveguide circuit demonstrated a strong electron cyclotron instability, producing a high efficiency (>20%) oscillation at 32.8 GHz. The interaction was first predicted from a particle-in-cell (PIC) code, MAGIC and agreed reasonably well with the measured performance. A design study on a 200 kW, 35 GHz two-cavity gyroklystron amplifier is in progress by the use of slow-time scale non-linear codes for beam-wave interactions, a finite element electromagnetic code, HFSS and a CASCADE code for cold cavity problems. MAGIC and SOS are also utilized to compare with those predictions. PIC-code simulation techniques and its comparison with measurements will be presented.