STATUS OF ELECTRON-CYCLOTRON WAVE TECHNOLOGY

A review of the two key technologies for the electron cyclotron wave ( ECW) system, the gyrotron source and the window, is presented. In both fields, significant progress has been made to meet the requirements o f the heating and current drive systems planned for devices such as W7 -X or ITER, namely 1 MW-CW (continuous wave) in the frequency range 14 0-170 GHz. Gyrotrons in this performance range have been tested in lon g pulse operation (many seconds). With the use of a diamond window, ex tremely long pulse (much greater than 10 s) or true CW operation is po ssible. Tests presently underway confirm such a promising behaviour of the window, paving the way towards the development of megawatt CW tub es.