Study on detachment scenario in fusion plasmas by the fast two-dimensional spectroscopic measurement of local density

2014 Fiscal Year Final Research Report

• Project/Area Number: 24360383
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Nuclear fusion studies
• Research Institution: National Institute for Fusion Science
• Principal Investigator: MIYAZAWA Junichi 核融合科学研究所, ヘリカル研究部, 准教授 (50300728)
• Co-Investigator(Renkei-kenkyūsha): MOTOJIMA Gen 核融合科学研究所, ヘリカル研究部, 准教授 (00509507) ; MORISAKI Tomohiro 核融合科学研究所, ヘリカル研究部, 教授 (60280591) ; GOTO Motoshi 核融合科学研究所, ヘリカル研究部, 准教授 (00290916) ; SHOJI Mamoru 核融合科学研究所, ヘリカル研究部, 准教授 (00280602) ; KOBAYASHI Masahiro 核融合科学研究所, ヘリカル研究部, 准教授 (30399307) ; AKIYAMA Tsuyoshi 核融合科学研究所, ヘリカル研究部, 准教授 (80370138) ; MASUZAKI Suguru 核融合科学研究所, ヘリカル研究部, 教授 (80280593)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 超音速ガスパフ / デタッチメント / 大型ヘリカル装置 / プラズマ実験 / 線強度法 / 二次元計測 / 高速カメラ / ヘリオトロン

Outline of Final Research Achievements

For realization of a fusion reactor, it has been desired to establish a method to mitigate the large heat load on a plasma-facing component called the divertor. In this study, a series of experiment using the supersonic gas flow has been performed in the Large Helical Device (LHD). A long Laval nozzle of 2.4 m length was used to produce the supersonic gas flow and to increase the local edge density of the plasmas. As a result, the plasma edge temperature was decreased and the radiation loss was increased successfully. Two-dimensional profile measurement of electron density and temperature has been conducted using the supersonic helium gas flow. Three line spectra of helium have been chosen for the line-intensity ratio method. In the edge region, the electron temperature profile shows a layer structure similar to that of magnetic surfaces, while the electron density profile has a peak at the position where the gas flow contacts with the plasma.

Free Research Field

核融合学、プラズマ理工学