Regimes for efficiency enhancement of fast-wave amplifiers

Summary form only given. Fast-wave devices find applications in various fields from radar to material processing as well as in many plasma relevant disciplines such as plasma diagnostics and plasma heating. Improving the efficiency of such devices, which operate in the centimetre to sub-millimetre region of the electromagnetic spectrum, would thus have the potential to enhance these fields providing a host of far reaching benefits. Two fast-wave amplifier devices, the Cyclotron Autoresonance Maser (CARM) amplifier and the Gyro-Travelling Wave Tube (Gyro-TWT) have been simulated in the particle-in-cell (PiC) code MAGIC-3D for the purposes of efficiency enhancement.