Plasma and Fusion Research
Volume 3, 018 (2008)
Regular Articles
- National Institute for Fusion Science, Toki 509-5292, Japan
Abstract
A new application using an electric impulse signal has been developed for electron density profile measurements in the Large Helical Device (LHD). Using an impulse waveform voltage, which has broadband frequency components, we constructed an ultrashort pulsed radar reflectometer with 28 channels in X-, Ka-, and U-band frequency components. The effect of the bandwidth of an inline band-pass filter was investigated, and was optimized. For a multiple-channel and multiple-frequency band system, a new switching technique and multiplexer were developed. Using the Abel inversion method, the reconstructed electron density profile was obtained from the delay time as a function of the probing frequency. Good agreement with other diagnostics was obtained.
Keywords
impulse, microwave radar, electron density profile, microwave reflectometer, LHD
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This paper may be cited as follows:
Tokihiko TOKUZAWA, Kazuo KAWAHATA, Yasuhiko ITO, Kenji TANAKA, Ichihiro YAMADA and LHD Experimental Group, Plasma Fusion Res. 3, 018 (2008).