Development of a dual frequency (110/138 GHz) gyrotron for JT-60SA and its extension to an oscillation at 82 GHz

Abstract

Abstract.A dual-frequency gyrotron, which can generate 110 GHz and 138 GHz waves independently, is being developed in JAEA to enable electron cyclotron heating (ECH) and current drive (ECCD) in a wider range of plasma discharge conditions of JT-60SA. Conditioning operation of the gyrotron toward 1 MW for 100 s, which is the target output power and pulse length for JT-60SA, is in progress without significant problems. Oscillations of 1 MW for 10 s and 0.5 MW for 198 s were obtained, so far, at both frequencies. Cooling water temperatures in the gyrotron and matching optics unit were saturated in the 198 s oscillation, and the observed maximum water temperature is sufficiently low. In addition to the above activity on the dualfrequency gyrotron development, an oscillation (0.3 MW for 20 ms) at 82 GHz was demonstrated as an additional frequency of the dual-frequency gyrotron. A possibility of the use of fundamental harmonic wave at 82 GHz in JT-60SA has been shown.

Gyrotron‐Forschung und ‐Entwicklung am KIT

“…Bisher arbeiten Fusionsgyrotrons immer bei einer festen Frequenz. Für die Plasmaexperimente ASDEX, JT-60SA und TCV werden aber bereits Gyro-trons entwickelt beziehungsweise sind in Betrieb, die alternativ bei zwei oder drei Frequenzen betrieben werden können [34][35][36]…”