Fully non-inductive plasma start-up with lower-hybrid waves using the outboard-launch and top-launch antennas on the TST-2 spherical tokamak
Removal of the central solenoid is essential to realize an economical spherical tokamak fusion reactor, but non-inductive plasma start-up is a challenge. On the TST-2 spherical tokamak, non-inductive plasma start-up using lower-hybrid (LH) waves has been investigated. Using the capacitively-coupled...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
EDP Sciences
2017-01-01
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| Series: | EPJ Web of Conferences |
| Online Access: | https://doi.org/10.1051/epjconf/201715702009 |
| _version_ | 1818618561822720000 |
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| author | Tsujii Naoto Takase Yuichi Ejiri Akira Shinya Takahiro Yajima Satoru Yamazaki Hibiki Togashi Hiro Moeller Charles P. Roidl Benedikt Takahashi Wataru Toida Kazuya Yoshida Yusuke |
| author_facet | Tsujii Naoto Takase Yuichi Ejiri Akira Shinya Takahiro Yajima Satoru Yamazaki Hibiki Togashi Hiro Moeller Charles P. Roidl Benedikt Takahashi Wataru Toida Kazuya Yoshida Yusuke |
| author_sort | Tsujii Naoto |
| collection | DOAJ |
| description | Removal of the central solenoid is essential to realize an economical spherical tokamak fusion reactor, but non-inductive plasma start-up is a challenge. On the TST-2 spherical tokamak, non-inductive plasma start-up using lower-hybrid (LH) waves has been investigated. Using the capacitively-coupled combline (CCC) antenna installed at the outboard midplane, fully non-inductive plasma current ramp-up up to a quarter of that of the typical Ohmic discharges has been achieved. Although it was desirable to keep the density low during the plasma current ramp-up to avoid the LH density limit, it was recognized that there was a maximum current density that could be carried by a given electron density. Since the density needed to increase as the plasma current was ramped-up, the achievable plasma current was limited by the maximum operational toroidal field of TST-2. The top-launch CCC antenna was installed to access higher density with up-shift of the parallel index of refraction. Numerical analysis of LH current drive with the outboard-launch and top-launch antennas was performed and the results were qualitatively consistent with the experimental observations. |
| first_indexed | 2024-12-16T17:23:33Z |
| format | Article |
| id | doaj.art-8daa32604d2f4295910fd51791fec678 |
| institution | Directory Open Access Journal |
| issn | 2100-014X |
| language | English |
| last_indexed | 2024-12-16T17:23:33Z |
| publishDate | 2017-01-01 |
| publisher | EDP Sciences |
| record_format | Article |
| series | EPJ Web of Conferences |
| spelling | doaj.art-8daa32604d2f4295910fd51791fec6782022-12-21T22:23:07ZengEDP SciencesEPJ Web of Conferences2100-014X2017-01-011570200910.1051/epjconf/201715702009epjconf_rfppc2017_02009Fully non-inductive plasma start-up with lower-hybrid waves using the outboard-launch and top-launch antennas on the TST-2 spherical tokamakTsujii NaotoTakase YuichiEjiri AkiraShinya TakahiroYajima SatoruYamazaki HibikiTogashi HiroMoeller Charles P.Roidl BenediktTakahashi WataruToida KazuyaYoshida YusukeRemoval of the central solenoid is essential to realize an economical spherical tokamak fusion reactor, but non-inductive plasma start-up is a challenge. On the TST-2 spherical tokamak, non-inductive plasma start-up using lower-hybrid (LH) waves has been investigated. Using the capacitively-coupled combline (CCC) antenna installed at the outboard midplane, fully non-inductive plasma current ramp-up up to a quarter of that of the typical Ohmic discharges has been achieved. Although it was desirable to keep the density low during the plasma current ramp-up to avoid the LH density limit, it was recognized that there was a maximum current density that could be carried by a given electron density. Since the density needed to increase as the plasma current was ramped-up, the achievable plasma current was limited by the maximum operational toroidal field of TST-2. The top-launch CCC antenna was installed to access higher density with up-shift of the parallel index of refraction. Numerical analysis of LH current drive with the outboard-launch and top-launch antennas was performed and the results were qualitatively consistent with the experimental observations.https://doi.org/10.1051/epjconf/201715702009 |
| spellingShingle | Tsujii Naoto Takase Yuichi Ejiri Akira Shinya Takahiro Yajima Satoru Yamazaki Hibiki Togashi Hiro Moeller Charles P. Roidl Benedikt Takahashi Wataru Toida Kazuya Yoshida Yusuke Fully non-inductive plasma start-up with lower-hybrid waves using the outboard-launch and top-launch antennas on the TST-2 spherical tokamak EPJ Web of Conferences |
| title | Fully non-inductive plasma start-up with lower-hybrid waves using the outboard-launch and top-launch antennas on the TST-2 spherical tokamak |
| title_full | Fully non-inductive plasma start-up with lower-hybrid waves using the outboard-launch and top-launch antennas on the TST-2 spherical tokamak |
| title_fullStr | Fully non-inductive plasma start-up with lower-hybrid waves using the outboard-launch and top-launch antennas on the TST-2 spherical tokamak |
| title_full_unstemmed | Fully non-inductive plasma start-up with lower-hybrid waves using the outboard-launch and top-launch antennas on the TST-2 spherical tokamak |
| title_short | Fully non-inductive plasma start-up with lower-hybrid waves using the outboard-launch and top-launch antennas on the TST-2 spherical tokamak |
| title_sort | fully non inductive plasma start up with lower hybrid waves using the outboard launch and top launch antennas on the tst 2 spherical tokamak |
| url | https://doi.org/10.1051/epjconf/201715702009 |
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