Studies of energetic particle transport induced by multiple Alfvén eigenmodes using neutron and escaping energetic particle diagnostics in Large Helical Device deuterium plasmas

Nuclear Fushion

article

K. Ogawa¹  M. Isobe¹  S. Kamio¹  H. Nuga¹  R. Seki¹  S. Sangaroon³  H. Yamaguchi¹  Y. Fujiwara¹  E. Takada⁴  S. Murakami⁵  J. Jo⁶  Y. Takemura¹  H. Sakai⁷  K. Tanaka¹  T. Tokuzawa¹  R. Yasuhara¹  M. Osakabe¹ 

[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;Kyushu University

关键词: energetic particle;    neutron;    Alfv´en eigenmode;    Large Helical Device;    deuteriumexperiment;    energetic particle transport;   

DOI  :  10.1088/1741-4326/ac6f66

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

Studies of energetic particle transport due to energetic-particle-driven Alfvénic instability have progressed using neutron and energetic particle diagnostics in Large Helical Device deuterium plasmas. Alfvénic instability excited by injecting an intensive neutral beam was observed by a magnetic probe and a far-infrared laser interferometer. The interferometer showed Alfvénic instability composed of three modes that existed from the core to the edge of the plasma. A comparison between the observed frequency and shear Alfvén spectra suggested that the mode activity was most likely classified as an Alfvénic avalanche. A neutron fluctuation detector and a fast ion loss detector indicated that Alfvénic instability induced transport and loss of co-going transit energetic ions. The dependence of the drop rate of the neutron signal on the Alfvénic instability amplitude showed that significant transport occurred. Significant transport might be induced by the large amplitude and radially extended multiple modes, as well as a large deviation of the energetic ion orbit from the flux surface.

【 授权许可】

Unknown