NIFS-846

FULL TEXT (PDF, 2891 KB)

Author(s): N. Ohno et al. Title: Bursty Fluctuation Characteristics in SOL/Divertor Plasmas of Large Helical Device Date of publication: Oct. 2006 Key words: 21 IAEA Fusion Energy Conference , EX/P4-20 Abstract: Bursty electrostatic fluctuation in the scrape off layer (SOL) and the divertor region of the Large Helical Device (LHD) have been investigated by using a Langmuir probe array on a divertor plate and a reciprocating Langmuir probe. Large positive bursty events were often observed in the ion saturation current measured with a divertor probe near the divertor leg at which the magnetic line of force connected to the area of a low-field side with a short connection length. Condition averaging result of the positive bursty events indicates the intermittent feature with a rapid increase and a slow decay is similar to that of plasma blobs observed in tokamaks. On the other hand, at a striking point with a long connection length, negative spikes were observed. Statistical analysis based on probability distribution function (PDF) was employed to investigate the bursty fluctuation property. The observed scaling exponents disagree with the predictions for the self-organized criticality (SOC) paradigm.

List of NIFS Report (2006)Return toContents Page Return toNIFS Homepage

National Institute for Fusion Science
		Copyright: 1995-2007 National Institute for Fusion Science (NIFS) Address: 322-6,Oroshi-cho, Toki, GIFU, 509-5292, Japan Telephone:+81-572-58-2222