Plasma and Fusion Research

Volume 14, 3403123 (2019)

Regular Articles

Prediction of Neutron Emission Anisotropy for Validation of an Analysis Model for Neutron Spectra in Beam-Injected LHD Deuterium Plasmas
Shota SUGIYAMA, Hideaki MATSUURA, Takuya GOTO1,2), Takeo NISHITANI1), Mitsutaka ISOBE1,2) and Kunihiro OGAWA1,2)
Applied Quantum Physics and Nuclear Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
1)
National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki 509-5292, Japan
2)
SOKENDAI (The Graduate University for Advanced Studies), 322-6 Oroshi-cho, Toki 509-5292, Japan
(Received 10 January 2019 / Accepted 12 May 2019 / Published 11 July 2019)

Abstract

We developed an analysis model to predict and describe neutron emission anisotropy caused by anisotropy of energetic deuterons in the large helical device (LHD), by considering energetic-ion distribution functions, the differential cross-section of fusion reactions, and the exact shape of the vacuum vessel of the LHD. Neutron emission anisotropy that can be observed by the neutron activation system is evaluated numerically assuming deuterium-beam-injected deuterium plasmas confined by the LHD using the model. We demonstrate the dependence of neutron emission anisotropy on the beam-injection direction and the electron temperature. Based on this estimation, we propose an experimental scenario to validate the analysis model and easily understand energetic-ion anisotropy caused by the neutral beam injection.

Keywords

neutron emission anisotropy, non-Maxwellian tail, neutron emission spectrum, neutral beam injection, deuterium plasma, Large Helical Device

DOI: 10.1585/pfr.14.3403123

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