Details

Autor(en) / Beteiligte

• Wang, Wei
• Xu, Liqing
• Gong, X.
• Qian, Jinping
• Zhang, Bin
• Zhao, Hailin
• Li, Pan
• Liu, Wenbin
• Liang, Ruirong
• Hu, Yunchan
• Wang, Zuhao
• Guo, Yutong
• Chao, Yan

Titel

Experiment study of m/n = 1/1 mode saturation level in high- βp discharge on the EAST tokamak

Ist Teil von

• Physics of plasmas, 2024-04, Vol.31 (4)

Ort / Verlag

Melville: American Institute of Physics

Erscheinungsjahr

2024

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The saturated internal kink mode with m/n = 1/1 has been observed in the H-mode discharge of the experimental advanced superconducting tokamak, characterized by high  βP and weak magnetic shear in the core. This observation was made using a combination of soft x-ray imaging and electron cyclotron emission diagnostics. It was noted that the repetitive bursting of m/n = 1/1 internal mode (large amplitude, short bursting duration) transitions into a long-lasting continuous one (small amplitude, constant frequency), when βp> 2.2 in H-mode, a much shorter bursting duration, transitioning into a long-lasting continuous one, with smaller amplitude and a constant frequency. Conversely, for typical βp< 1.5 in L/I discharge, the frequency of m/n = 1/1 mode decreases with time, associated with local poloidal electron diamagnetism drift velocity. The benign m/n = 1/1 mode in high βp has an amplitude much smaller than one in L-mode for high βP stabilization effect. By adjusting the power deposition of electron cyclotron resonance heating, it is found that the saturation level of m/n = 1/1 mode is independent of the local electron temperature gradient in H-mode discharge. It underscores that the flat current and, hence, weak magnetic shear are crucial factors influencing the saturation level of the m/n = 1/1 mode for both the off-axis electron cyclotron current driving current-dominant and off-axis bootstrap current-dominant cases. Furthermore, the outward movement with growth of the m/n = 1/1 mode in the process of L-H mode transition and the characteristic time of this process are close to the current diffusion time.