Plasma and Fusion Research

Volume 16, 2402044 (2021)

Regular Articles

Initial Results of Hydrogen and Deuterium Beam Ion Simultaneous Transport due to Toroidal Alfvén Eigenmode in the Large Helical Device
Shuji KAMIO1), Yutaka FUJIWARA1), Kunihiro OGAWA1,2), Ryosuke SEKI1,2), Kenichi NAGAOKA1,3), Hideo NUGA1), Siriyaporn SANGAROON1,4), Mitsutaka ISOBE1,2), Masaki OSAKABE1,2), Chio-Zong CHENG5,6) and the LHD Experiment Group
1)
National Institute for Fusion Science, National Institute of Natural Sciences, 322-6 Oroshi-cho, Toki 509-5292, Japan
2)
The Graduate University for Advanced Studies, SOKENDAI, 322-6 Oroshi-cho, Toki 509-5292, Japan
3)
Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
4)
Mahasarakham University, 20-41 Kamriang, Kantharawichai, Mahasarakham 44150, Thailand
5)
The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8561, Japan
6)
Princeton University, Princeton, New Jersey 08543, USA
(Received 8 December 2020 / Accepted 9 February 2021 / Published 19 March 2021)

Abstract

The behavior of energetic particles (EPs) associated with toroidal Alfvén eigenmode (TAE) activities during the combined injection of hydrogen and deuterium beams was investigated in the Large Helical Device (LHD). The enhanced transports of both proton and deuteron with TAE activities were simultaneously observed by a tangentially viewing and mass and energy resolved neutral particle analyzer (E||B-NPA). At the timing of the TAE bursts with the mode number n = 1, both proton and deuteron were transported to the outboard and observed with the similar energies of 137 - 138 keV. At the peak amplitude of the magnetic fluctuations measured by the Mirnov coils, the mixed frequencies of 64 kHz and 29 kHz were identified, and the observed frequencies did not chirp down. The observed timings of the transported hydrogen and deuterium were just after the magnetic fluctuations of 64 kHz and 29 kHz, respectively. By adapting the cross-correlation analysis, the delay times from the magnetic fluctuation to the detection of EPs by E||B-NPA are estimated to 95 μs and 145 μs for hydrogen and deuterium, respectively. These delays are considered to be the time of the radial transport, and the time delays depended on the velocities of the transported EPs.

Keywords

toroidal Alfvén eigenmode, TAE burst, neutral particle analyzer

DOI: 10.1585/pfr.16.2402044

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