Observation of intermittency in edge plasma of SUNIST tokamak
Feng Chun-Huaa, Wang Wen-Haob, He Ye-Xib, Gao Zheb, Zeng Lib, Zhang Guo-Pingb, Xie Li-Fengb
a Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China; b Department of Engineering Physics, Tsinghua University, Beijing 100084, China
Abstract The temporal intermittency of the fluctuation-driven particle transport fluxes is analysed by using data obtained from Langmuir probe array in the edge of the Sino-United Spherical Tokamak (SUNIST). The conditional statistics analysis indicates that the intermittent structures have a characteristic time width of about 30μs, which is the typical fluctuation time scaling. It is also found that the transport fluxes have a multifractal character over the fluctuation time scales, and exhibit a long-time-range correlation character with self-similar parameter H>0.5 in the plasma confinement time scales. Furthermore, the analyses show that the level of the intermittency and the long-range correlation of the fluxes vary with increasing plasma density. These observations are consistent with the prediction of the avalanche-like model.
Received: 21 June 2004
Revised: 20 August 2004
Published: 17 March 2005