Study of a plasma radial diffusion by injecting a pellet

• Project/Area Number: 60580008
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: プラズマ理工学
• Research Institution: Institute of Plasma Physics of Nagoya University
• Principal Investigator: KUMAZAWA Ryuhei Institute of Plasma Physics of Nagoya University, プラズマ研究所, 助手 (70109354)
• Co-Investigator(Kenkyū-buntansha): SATO Konosuke Institute of Plasma Physics of Nagoya University, プラズマ研究所, 助教授 (80023737) ; HATORI Tadatugu Institute of Plasma Physics of Nagoya University, プラズマ研究所, 助教授 (80023729) ; OKAMURA Shoichi Institute of Plasma Physics of Nagoya University, プラズマ研究所, 助手 (60115540) ; ADATI Keizo Institute of Plasma Physics of Nagoya University, プラズマ研究所, 助教授 (30023716) ; SATO Teruyuki Institute of Plasma Physics of Nagoya University, プラズマ研究所, 教授 (70023702)
• Project Period (FY): 1985 – 1986
• Project Status: Completed (Fiscal Year 1986)
• Budget Amount: ¥1,700,000 (Direct Cost: ¥1,700,000); Fiscal Year 1986: ¥200,000 (Direct Cost: ¥200,000); Fiscal Year 1985: ¥1,500,000 (Direct Cost: ¥1,500,000)
• Keywords: Open ended fusion device / pellet injection / 径方向拡散

Research Abstract

It is one of the most important issue to investigate a radial diffusion across a magnetic field in researching the fusion plasma. We have proposed a new method to investigate a radial diffusion of the plasma. In this method, a pellet is injected into a plasma and a behavior of impurities emitted from the pellet is observed. We can deduce the radial diffusion coefficient from the time and spatial behavior of impurities. This study has been carried out for 2 years scince 1985.
In the first year, we made a pellet dropping device and confirmed that the pellet dropped in the good reproducibility of time. The free dropping pellet was optically caught by a pellet detector system and this signal is used as a main trigger to get a high temperature and density plasma. At the next year, this whole device was attached to RFC-XX-M device and the carbon pellet was injected to the mirror plasma at the central cell, whose electron density, ion temperature and electron temperature are 5 x <10^(12)> <cm^(-3)> , 500 eV and 25 eV, respectively. We have deduced a radial diffusion coefficient to be D = 5 x <10^3> <cm^2> /sec from the comparison between the measured CIII light (4647.4 <ang> ) signal and one-dimentional diffusion equation. Then the radial diffusion time constant ( <tau_(Perpendicular)> ) is calculated to be <tau_(Perpendicular)> = <a^2> /6D = 3 ms where a is a plasma radius (a = 10 cm). This value is much larger than the measured particle and energy confinement time which are 0.3 ms and 0.2 ms, respectively. We think we could deduce sucessfully the radial diffusion coefficient by injecting carbon pellet into the plasma.

Research Products

• [Publications] 熊澤隆平,佐藤照幸,岡林昇一,足立圭三,青木高之,藤田秀樹,秀熊茂,河本俊和,増本博,西村清彦,等: 第11回IAEA国際会議-プラズマ物理と制御核融合(京都,日本). IAEA-CN-47C-
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] R. Kumazawa, T. Sato, S. Okamura, K. Adati, T. Aoki, H. Fujita, S. Hidekuma, T. Kawamoto H. Masumoto, K. Nishimura, T. Hatori, K. Takayama: "RF Plugging and Tandem Mirror Experiments in a Cusp-Anchored Mirror Device" 11th International Conference on Plasma Physics and Controlled Nuclear Fusion Research (Kyoto, Japan), 1986. IAEA-CN-47/C- <II> -6 (1986)
  • Description: 「研究成果報告書概要(欧文)」より