Open AccessA study of beam ion and deuterium–deuterium fusion-born triton transports due to energetic particle-driven magnetohydrodynamic instability in the large helical device deuterium plasmas
Author(s) -
K. Ogawa,
M. Isobe,
Hideo Nuga,
S. Kamio,
Y. Fujiwara,
Makoto Kobayashi,
Siriyaporn Sangaroon,
Eiji Takada,
R. Seki,
Hiroyuki Yamaguchi,
S. Murakami,
Junghyo Jo,
M. Osakabe
Publication year - 2021
Publication title -
nuclear fusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.774
H-Index - 120
eISSN - 1741-4326
pISSN - 0029-5515
DOI - 10.1088/1741-4326/ac0d8a
Subject(s) - deuterium , atomic physics , ion , neutron , plasma , nuclear physics , chemistry , physics , organic chemistry
Understanding energetic particle transport due to magnetohydrodynamic instabilities excited by energetic particles is essential to apprehend alpha particle confinement in a fusion burning plasma. In the large helical device (LHD), beam ion and deuterium–deuterium fusion-born triton transport due to resistive interchange mode destabilized by helically-trapped energetic ions (EIC) are studied employing comprehensive neutron diagnostics, such as the neutron flux monitor and a newly developed scintillating fiber detector characterized by high detection efficiency. Beam ion transport due to EIC is studied in deuterium plasmas with full deuterium or hydrogen/deuterium beam injections. The total neutron emission rate ( S n ) measurement indicates that EIC induces about a 6% loss of passing transit beam ions and a 60% loss of helically-trapped ions. The loss rate of helically-trapped ions, which drive EIC, is larger than the loss rate of passing transit beam ions. Furthermore, the drop of S n increasing linearly with the EIC amplitude shows that barely confined beam ions existing near the confinement-loss boundary are lost due to EIC. In full deuterium conditions, a study of deuterium–deuterium fusion-born triton transport due to EIC is performed by time-resolved measurement of total secondary deuterium–tritium neutron emission rate ( S n_DT ). Drop of S n_DT increases substantially with EIC amplitude to the third power and reaches up to 30%. The relation shows that not only tritons confined in confined-loss boundary, but also tritons confined in the inner region of a plasma, are substantially transported.