Measurement of edge density profiles of Large Helical Device plasmas using an ultrashort-pulse reflectometer.
We report here on the application of an ultrashort-pulse reflectometer (USPR) to Large Helical Device in National Institute for Fusion Science. An impulse with picosecond pulse width is used as a source in an USPR. Since the bandwidth of a source is inversely related to the pulse width, we can utilize the frequency range of microwave to millimeter-wave by using wide band transmission lines. The density profiles can be reconstructed by collecting time-of-flight signal of each frequency component of an impulse reflected from each cutoff layer. Remote control system using super science information network has been introduced to the present USPR system.
Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga 816-8580, Japan. yokotay5@asem.kyushu-u.ac.jp
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Yokota
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Mase
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Kogi
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Bruskin
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Tokuzawa
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Kawahata