TY - JOUR
T1 - Electron cyclotron emission measurements by means of a grating polychromator on the large helical device
AU - De Vries, P. C.
AU - Kawahata, K.
AU - Nagayama, Y.
AU - Inagaki, S.
AU - Sasao, H.
AU - Ito, Y.
N1 - Funding Information:
The work presented in this paper has been performed with financial support of the Japan Society of Promotion of Science and the National Institute for Fusion Science.
PY - 2001/1
Y1 - 2001/1
N2 - The electron cyclotron emission (ECE) spectrum at the large helical device (LHD) is measured by a 14-channel grating polychromator. During standard operation, the polychromator monitors second harmonic frequencies (100-150 GHz). At sufficient high density, the second harmonic X-mode polarisation is optically thick and can be used to determine the temperature profile. However, the large magnetic field shear in LHD affects the ECE polarisation. This effect has been studied numerically. The wave polarisation was found to rotate in the laboratory frame. Eperiments have been carried out by means of a polarisation rotator in the diagnostic waveguide system, which confirmed the calculations. By a proper setting of the polarisation rotator, the rotation can be corrected and pure X-mode is detected. Temperature profiles have been measured successfully by the polychromator.
AB - The electron cyclotron emission (ECE) spectrum at the large helical device (LHD) is measured by a 14-channel grating polychromator. During standard operation, the polychromator monitors second harmonic frequencies (100-150 GHz). At sufficient high density, the second harmonic X-mode polarisation is optically thick and can be used to determine the temperature profile. However, the large magnetic field shear in LHD affects the ECE polarisation. This effect has been studied numerically. The wave polarisation was found to rotate in the laboratory frame. Eperiments have been carried out by means of a polarisation rotator in the diagnostic waveguide system, which confirmed the calculations. By a proper setting of the polarisation rotator, the rotation can be corrected and pure X-mode is detected. Temperature profiles have been measured successfully by the polychromator.
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U2 - 10.1016/S0920-3796(00)00496-8
DO - 10.1016/S0920-3796(00)00496-8
M3 - Article
AN - SCOPUS:0034951321
VL - 53
SP - 185
EP - 191
JO - Fusion Engineering and Design
JF - Fusion Engineering and Design
SN - 0920-3796
IS - 1-4
ER -