Direct measurement of refracted trajectory of transmitting electron cyclotron beam through plasma on the Large Helical Device
1 National Institute for Fusion Science, Toki 509-5292, Japan
2 Institute of Advanced Energy, Kyoto Univ., Uji 611-0011, Japan
3 Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-17491 Greifswald, Germany
a Corresponding author: takahashi.hiromi@LHD.nifs.ac.jp
Published online: 12 March 2015
The electron-cyclotron (EC) -beam refraction due to the presence of plasma was investigated in the Large Helical Device. The transmitted-EC-beam measurement system was constructed and the beam pattern on the opposite side of the irradiated surface was measured using an IR camera. Clear dependence of the EC-beam refraction on the electron density was observed and the beam shift in the toroidal direction showed good agreement with the ray-trace calculation of TRAVIS. The influence of the peripheral density profile and the thermal effect on the beam refraction were discussed.
© Owned by the authors, published by EDP Sciences, 2015
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