Development of an outer-off-midplane lower hybrid wave launcher for improved core absorption in non-inductive plasma start-up on TST-2

被引:3
作者
Ko, Y. [1 ]
Tsujii, N. [1 ]
Ejiri, A. [1 ]
Watanabe, O. [1 ]
Jang, S. [1 ]
Shinohara, K. [1 ]
Iwasaki, K. [1 ]
Peng, Y. [1 ]
Lin, Y. [1 ]
Shirasawa, Y. [1 ]
Hidano, T. [1 ]
Adachi, F. [1 ]
Tian, Y. [1 ]
机构
[1] Univ Tokyo, Kashiwa 2778561, Japan
关键词
spherical tokamak; lower hybrid wave; non-inductive plasma start-up; traveling wave antenna; SPHERICAL TOKAMAK; ECH;
D O I
10.1088/1741-4326/acf5ff
中图分类号
O35 [流体力学]; O53 [等离子体物理学];
学科分类号
070204 ; 080103 ; 080704 ;
摘要
A new outer-off-midplane lower hybrid (LH) wave launcher was developed for improved core absorption in the TST-2 spherical tokamak. In the previously developed outer-midplane and top launch scenarios, plasma current was driven only very near the plasma edge (r/a > 0.7), resulting in limited driven current density. Strong thick-target x-ray radiation has also been observed for the top launch scenario, which indicated LH wave driven fast electron losses. The outer-off-midplane launch scenario was designed to drive current at the core (r/a similar to 0.5) at low phase velocity to suppress production of unnecessarily high energy electrons. In the non-inductive plasma start-up experiment with the new outer-off-midplane launch scenario, improved core electron heating was confirmed by the Thomson scattering diagnostic that showed the electron temperature was about twice as high as the previous two scenarios. Reduction of the LH wave driven fast electron losses was confirmed by the measured x-ray radiation intensity that was substantially lower than the top launch scenario. It was also easier to maintain the optimum level of the electron density compared to the outer-midplane launch scenario that indicated the undesired LH wave interactions with the scrape-off-layer plasma may have been reduced due to strong core absorption.
引用
收藏
页数:10
相关论文
共 20 条
  • [1] [Anonymous], COMS MULT
  • [2] [Anonymous], LTspice-design center-analog devices
  • [3] The first lower hybrid current drive experiments in the spherical tokamak Globus-M
    Dyachenko, V. V.
    Shcherbinin, O. N.
    Gusakov, E. Z.
    Gusev, V. K.
    Irzak, M. A.
    Kurskiev, G. S.
    Petrov, Yu. V.
    Saveliev, A. N.
    Sakharov, N. V.
    Khitrov, S. A.
    Khromov, N. A.
    Varfolomeev, V. I.
    Voronin, A. V.
    [J]. NUCLEAR FUSION, 2015, 55 (11)
  • [4] A Fast Electron Transport Model for Lower Hybrid Wave Sustained Plasmas
    Ejiri, Akira
    Yamazaki, Hibiki
    Takase, Yuichi
    Tsujii, Naoto
    Watanabe, Osamu
    Peng, Yi
    Iwasaki, Kotaro
    Aoi, Yuki
    Ko, Yongtae
    Matsuzaki, Kyohei
    Rice, James H. P.
    Osawa, Yuki
    Moeller, Charles P.
    Yoshimura, Yasuo
    Kasahara, Hiroshi
    Saito, Kenji
    Seki, Tetsuo
    Kamio, Shuji
    [J]. PLASMA AND FUSION RESEARCH, 2022, 17
  • [5] Lower hybrid wave excitation and propagation in the spherical tokamak Globus-M
    Gusakov, E. Z.
    Dyachenko, V. V.
    Irzak, M. A.
    Khitrov, S. A.
    Saveliev, A. N.
    Shcherbinin, O. N.
    [J]. PLASMA PHYSICS AND CONTROLLED FUSION, 2010, 52 (07)
  • [6] Non-Inductive Start up of QUEST Plasma by RF Power
    Hanada, K.
    Zushi, H.
    Idei, H.
    Nakamura, K.
    Ishiguro, M.
    Tashima, S.
    Kalinnikova, E. I.
    Sakamoto, M.
    Hasegawa, M.
    Fujisawa, A.
    Higashijima, A.
    Kawasaki, S.
    Nakashima, H.
    Liu, H.
    Mitarai, O.
    Maekawa, T.
    Fukuyama, A.
    Takase, Y.
    Qian, J.
    [J]. PLASMA SCIENCE & TECHNOLOGY, 2011, 13 (03) : 307 - 311
  • [7] Harvey R.W., 1992, The CQL3D Fokker-Planck Code GA-A20978 General Atomics
  • [8] Formation of spherical tokamak equilibria by ECH in the LATE device
    Maekawa, T
    Terumichi, Y
    Tanaka, H
    Uchida, M
    Yoshinaga, T
    Yamaguchi, S
    Igami, H
    Konno, M
    Katsuura, K
    Hayashi, K
    Abe, Y
    Yamada, J
    Maebara, S
    Imai, T
    [J]. NUCLEAR FUSION, 2005, 45 (11) : 1439 - 1445
  • [9] Maekawa T, 2003, AIP CONF PROC, V694, P340, DOI 10.1063/1.1638054
  • [10] Spherical torus concept as power plants - the ARIES-ST study
    Najmabadi, F
    [J]. FUSION ENGINEERING AND DESIGN, 2003, 65 (02) : 143 - 164