[Table of Contents]

Plasma and Fusion Research

Volume 6, 1402135 (2011)

Regular Articles


Observation of Electron-Temperature Fluctuations Triggered by Supersonic Gas Puffing in the LHD
Akiyoshi MURAKAMI, Junichi MIYAZAWA1), Koji YASUI1), Takanori MURASE1), Naoki TAMURA1), Hayato TSUCHIYA1), Yoshiro NARUSHIMA1), Tomohiro MORISAKI1), Ryuichi SAKAMOTO1), Hiroshi YAMADA1) and LHD Experiment Group1)
The Graduate University for Advanced Studies, 322-6 Oroshi-cho, Toki 509-5292, Japan
1)
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan
(Received 4 April 2011 / Accepted 9 August 2011 / Published 21 October 2011)

Abstract

Non-local transport and electron temperature fluctuations triggered by supersonic gas puffing (SSGP) in high-temperature helical plasmas in the Large Helical Device (LHD) are reported. After a short-pulse SSGP, the core electron temperature increased while the edge electron temperature decreased. SSGP triggered a longer core temperature increase than that triggered by a small impurity pellet injection. The temperature profile, which was relatively flat inside the half minor radius before SSGP, became parabolic after non-local transport was triggered. Fluctuations were excited in the electron temperature signals around the half minor radius. The frequency of these fluctuations increased from ∼ 400 Hz to ∼ 1 kHz within ∼ 0.1 s and the amplitude decreased correspondingly. The temperature fluctuations inside and outside of the half minor radius had opposite phases. Magnetic fluctuations resonating near the half minor radius were observed simultaneously with the electron temperature fluctuations.


Keywords

fueling method, supersonic gas puffing, electron temperature fluctuation, non-local transport phenomenon, heliotron

DOI: 10.1585/pfr.6.1402135


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This paper may be cited as follows:

Akiyoshi MURAKAMI, Junichi MIYAZAWA, Koji YASUI, Takanori MURASE, Naoki TAMURA, Hayato TSUCHIYA, Yoshiro NARUSHIMA, Tomohiro MORISAKI, Ryuichi SAKAMOTO, Hiroshi YAMADA and LHD Experiment Group, Plasma Fusion Res. 6, 1402135 (2011).