STATUS OF DEVELOPMENT OF THE 2MW, 170GHz COAXIAL-CAVITY GYROTRON FOR ITER

A collaborative effort between European research Associations and Thales Electron Devices (TED) has been launched by the European Fusion Development Agreement (EFDA) in 2003, aiming at the development of an industrial 170GHz/2MW/CW coaxial cavity gyrotron. The first prototype is expected to reach 2MW/1s and is presently being tested in Lausanne at a dedicated test facility. The test facility has been designed to be flexible: allowing the possible commissioning of tubes with different characteristics, as well the tests of a version of the ITER upper launcher antenna at full performances. The test facility has been commissioned during the first test phases on the gyrotron which include: high voltage stand-off, coaxial insert alignment and cathode conditioning without depressed collector power supply at a slightly reduced electron beam power of 85kV/78A/2ms. The short pulse (<5ms) operation of the gyrotron has demonstrated stable single mode operation in the designed TE(-34,19) mode at RF power levels in excess of 1.4MW, at below nominal electron beam parameters (79kV/75A). Further RF optimization in view of reaching the nominal beam parameters of 90kV/75A is presently underway and the status of the short pulse (< 100ms) experimental results will be reported.