A cyclotron maser using a spatially nonlinear electrostatic field

An electron cyclotron maser instability has been investigated [1] which was found to exist when a strong spatially nonlinear static electric field is applied to a system of electrons in cyclotron motion. This is a fast wave amplification mechanism. An energy dependent resonance frequency equation was derived from the nonlinear equation of motion and a method was formulated to readily allow calculation for a particular field configuration. Phase bunching was predicted and the growth rate for amplification of microwaves. The calculations show that amplification can occur for very low energy electrons of only a few electron-volts, provided that the non-linearity of the static field is strong. A preliminary experiment demonstrated the existence of the instability.