Application of ECW to the JT-60U Tokamak

Hoshino, Katsumichi; JT-60 Team

The pulse width of the electron cyclotron wave (ECW) is extending according to the long pulse operation of JT-60U and the ECW provides an important method to the experimental research aiming at the performance improvement of the JT-60U. ECW has features that the wave has good access to the plasma and capable of local heating or local current drive. In JT-60U, the ECW is applied, due to these features, to the recent physical study of the neoclassical tearing mode suppression, sawtooth control, study on the transport coefficient, study on the internal transport barrier and study of the current hole. Also, the ECW is applied for the tokamak start up without center solenoid for its feature of the good matching to the vacuum. As the ECH system does not suffer the effect of disruptions, it is applied for the start up assist and shut down assist in the condition that the wall is near the saturation condition and decreases the necessity of the discharge cleaning. These recent studies with the application of the ECW will be presented in the invited presentation.