Plasma start-up experiment and modelling on the TST-2 spherical tokamak

Y. Takase*, A. Ejiri, N. Tsujii, S. Yajima, Y. Aoi, Y. Iida, K. Iwasaki, Y. Kawamata, Y. Ko, K. Matsuzaki, C. P. Moeller, Y. Peng, J. Rice, S. Sakamoto, H. Yamazaki, Y. Yoshida

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Plasma start-up experiments using the lower hybrid wave (LHW) were performed on the TST-2 spherical tokamak. Two capacitively-coupled combline antennas (outboard-launch and top-launch) are presently being used. Bottom-launch can be simulated using the top-launch antenna with reversed toroidal field. The unexpectedly good result of the simulated bottom-launch case was investigated by a combined ray-tracing and Fokker-Planck analysis. In the case of simulated bottom-launch the parallel index of refraction (n||) downshifts initially, but because of the plateau formed by the upshifted n|| LHW after reflecting from the cut-off layer at the bottom of the plasma, strong absorption of the low n|| LHW occurs during the first pass through the plasma, generating a distribution function which extends to very high energies.

Original languageEnglish (US)
Title of host publication23rd Topical Conference on Radiofrequency Power in Plasmas
EditorsPaul T. Bonoli, Robert I. Pinsker, Xiaojie Wang
PublisherAmerican Institute of Physics Inc.
ISBN (Electronic)9780735420137
DOIs
StatePublished - Sep 16 2020
Event23rd Topical Conference on Radiofrequency Power in Plasmas - Hefei, China
Duration: May 14 2019May 17 2019

Publication series

NameAIP Conference Proceedings
Volume2254
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

Conference23rd Topical Conference on Radiofrequency Power in Plasmas
Country/TerritoryChina
CityHefei
Period5/14/195/17/19

Funding

This work was supported in part by Japan/US Cooperation in Fusion Research and Development, Japan Ssociety for the Promotion of Science Grants-in-Aid for Scientific Research (S) 21226021 and (A) 21246137, US Department of Energy Cooperative Agreement DE-AC03-97ER-54411, National Institute for Fusion Science Collaboration Research Programs NIFS14KOCR001, NIFS18KOAR022 and NIFS16KNWR 002. Collaborations with P. Bonoli, J. Wright, and J. Lee at MIT on GENRAY/CQL3D calculations are gratefully acknowledged.

ASJC Scopus subject areas

  • General Physics and Astronomy

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