[Table of Contents]

Plasma and Fusion Research

Volume 3, 002 (2008)

Letters

2-D PSD Diagnostic System for the Pellet Trajectory in LHD Plasmas
Mitsuyasu HOSHINO, Ryuichi SAKAMOTO1), Hiroshi YAMADA1,2), Yasuhiko ITOH1), Kohki KUMAGAI2), Ryuhei KUMAZAWA1), Tetsuo WATARI1) and the LHD Experimental Group1)
Department of Energy Engineering and Science, Nagoya University, Nagoya 464-8603, Japan
1)
National Institute for Fusion Science, Toki 509-5292, Japan
2)
The Graduate University for Advanced Studies, SOKENDAI, Hayama 240-0193, Japan
(Received 12 July 2007 / Accepted 26 November 2007 / Published 10 January 2008)

Abstract

Ablation of a solid hydrogen pellet in hot plasmas of Large Helical Device (LHD) has been studied. A position sensitive detector (PSD) diagnostics has been newly installed to measure the trajectory of ablating pellets. 2-D diagnostics enables the measurement with high time (1 MHz) and spatial resolutions (80 μm). A 3-D pellet trajectory can be described by a combination of 2-D images and information of initial pellet direction and velocity. A deflection of the pellet trajectory in the neutral beam injection (NBI) heated plasmas of LHD has been observed. Means of improving the measurement accuracy of this system are also discussed.

Keywords

fueling, solid hydrogen, ablation, pellet trajectory, position sensitive detector, rocket effect, Large Helical Device

DOI: 10.1585/pfr.3.002

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This paper may be cited as follows:

Mitsuyasu HOSHINO, Ryuichi SAKAMOTO, Hiroshi YAMADA, Yasuhiko ITOH, Kohki KUMAGAI, Ryuhei KUMAZAWA, Tetsuo WATARI and the LHD Experimental Group, Plasma Fusion Res. 3, 002 (2008).