Responses of ion and electron channels to electron cyclotron heating in JT-60U

Yoshida, Maiko; Ide, Shunsuke; Takenaga, Hidenobu; Honda, Mitsuru; Urano, Hajime; Kobayashi, Takayuki; Nakata, Motoki; Miyato, Naoaki; Kamada, Yutaka

In this study, the temporal and spatial responses of electron channels and ion channels to central electron cyclotron heating (ECH) have been investigated in positive shear H-mode plasmas and weak shear plasmas with internal transport barriers (ITBs) on JT-60U. The flattening of ne profile is observed after the increase in Te in the core region. Linear gyrokinetic stability analyses predict that the growth rate of the trapped electron modes, which increase outward particle flux, becomes more pronounced during ECH. Ion temperature around the ITB foot rapidly reduces and the increase in Te precedes the reduction in Ti. From the observations and theoretical analyses, the reduced Ti can be interpreted as the decrease in the critical temperature gradient for the ion temperature gradient mode with ECH. The counter intrinsic rotation with ECH is identified on H-mode plasmas with small torque input where co-current NBs and counter-current NBs are simultaneously injected with the same power.