A 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

Nuclear Fushion

article

Y. Fujiwara¹  M.I. Kobayashi¹  S. Sangaroon¹  E. Takada⁴  R. Seki¹  H. Yamaguchi¹  S. Murakami⁵  J. Jo⁶  M. Osakabe¹  K. Ogawa¹  M. Isobe¹  H. Nuga¹  S. Kamio¹ 

[1] National Institute for Fusion Science, National Institutes of Natural Sciences;The Graduate University for Advanced Studies;Mahasarakham University;National Institute of Technology, Toyama College;Kyoto University;Korea Institute of Fusion Science

关键词: large helical device;    energetic particle confinement;    magnetohydrodynamicinstability;    neutron diagnostics;   

DOI  :  10.1088/1741-4326/ac0d8a

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

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 ofS _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 ofS _{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.

【 授权许可】

Unknown