The reflection influence at powerful gyrotron complex operation

Powerful gyrotrons are used for fusion plasma heating and current drive under ECR conditions in such devices as TOKAMAKs and STELLARATORs. Electrodynamic system of gyrotrons and microwave transmitting lines may contain different types of reflections of microwave power from line components, dielectric windows, chamber walls, etc. The reflected signal gets into operating volume of gyrotron cavity changing the conditions of electron beam interaction with RF field. The dependencies of output parameters on reflection coefficient and delay time were investigated. Estimation of the conditions for oscillation stability and enhancement of output signal spectrum in the presence of a reflected signal is given