H-Mode-Like Discharge under the Presence of 1⁄1 Rational Surface at Ergodic Layer in LHD

抄録

H-mode-like discharge was found in LHD with a full B_t field of 2.5 T at an outwardly shifted configuration of R_ax = 4.00 m where the m⁄n = 1⁄1 rational surface is located at the ergodic layer. The H-mode-like discharge was triggered by changing the P_NBI from 9 MW to 5 MW in a density range of 4-8 × 10¹³ cm^-3, followed by a clear density rise, ELM-like H_α bursts, and a reduction of magnetic fluctuation. These H-mode-like features vanished with a small radial movement of the 1⁄1 surface.