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Analysis on Relation Between Magnetic Structure and Bursty Fluctuation in SOL/Divertor Plasmas of LHD
Author(s) -
Ohno N.,
Masuzaki S.,
Miyoshi H.,
Takamura S.,
Budaev V. P.,
Morisaki T.,
Ohyabu N.,
Komori A.
Publication year - 2006
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/ctpp.200610065
Subject(s) - divertor , plasma , skewness , physics , morlet wavelet , large helical device , atomic physics , helicon , magnetic field , kurtosis , langmuir probe , computational physics , nuclear physics , plasma diagnostics , tokamak , wavelet , statistics , wavelet transform , mathematics , quantum mechanics , computer science , discrete wavelet transform , artificial intelligence
We have investigated a relation between the edge magnetic structure of the Large Helical Device (LHD) and the fluctuation properties of the ion saturation currents I sat measured by a Langmuir probe array (16 channels) embedded in an outboard divertor plate. The edge magnetic structure is calculated by KMAG and Watanabe codes. The fluctuation properties are analyzed based on the probability distribution function (p.d.f.) and complex Morlet wavelet decomposition. Large positive skewness was obtained from I sat measured at a low field side of a divertor leg and negative skewness was observed at striking point of the divertor leg, where the connection length of magnetic line of force is long. The fluctuation characteristics has very weak dependence of plasma density and its gradient. Waiting time statistics was analyzed to indicate that the waiting time statistics is not a Poisson process and there is no clear signature of SOC paradigm. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)