State-of-the-art of high power gyro-devices and free electron masers. Update 1995

Gyrotron oscillators are mainly used as high power millimeter wave sources for electron cyclotron resonance heating (ECRH) and diagnostics of magnetically confined plasmas for generation of energy by controlled thermonuclear fusion. 140 GHz (110 GHz) gyrotrons with output power P_o_u_t=0.54 MW (0.93 MW), pulse length #tau#=3.0 s (2.0 s) and efficiency #eta#=40% (38%) are commercially available. Total efficiencies around 50% have been achieved using single-stage depressed collectors. Diagnostic gyrotrons deliver P_o_u_t=40 kW with #tau#=40 #mu#s at frequencies up to 650 GHz (#eta##>=#4%). Recently, gyrotron oscillators have also been successfully used in materials processing. Such technological applications require gyrotrons with the following parameters: f#>=#24 GHz, P_o_u_t=10-50 kW, CW, #eta##>=#30. This paper gives an update of the experimental achievements related to the development of high power gyrotron oscillators for long pulse or CW operation and pulsed diagnostic gyrotrons. In addition, this work gives a short overview of the present development of gyrotrons for technological applications, relativistic gyrotrons, quasi-optical gyrotrons, cyclotron autoresonance masers (CARMs), gyroklystons, gyro-TWT amplifiers, gyrotwystron amplifiers, gyro-BWO's, gyropeniotrons and free electron masers (FEMs). The most impressive FEM output parameters are: P_o_u_t=2 GW, #eta#=20 ns, #eta#=13% at 140 GHz (LLNL) and P_o_u_t=15 kW, #tau#=20 #mu#s, #eta#=5% in the range from 120 to 900 GHz (UCSB). (orig.)182 refs.Available from TIB Hannover: ZA 5141(5728) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman