Application of the Gyrotron FU II Submillimeter Wave Radiation Source to Plasma Scattering Measurements
Source: International Journal of Infrared and Millimeter Waves, Volume 25, Number 11, November 2004 , pp. 1567-1579(13)
Abstract:Gyrotron FU II has been successfully applied as a submillimeter wave radiation source to plasma scattering measurements on the Compact Helical System (CHS) in National Institute for Fusion Science (NIFS) in Japan. The gyrotron operates in a long pulse mode (the pulse width is about 600 ms) at a frequency of about 350 GHz (the corresponding wavelength is 0.85 mm). The output power is about 110 W. The output power is transmitted along a circular waveguide system and converted to a Gaussian‐like beam by a quasi‐optical antenna. After that, the beam is directed onto the CHS plasma and the scattered signal is detected by a homodyne detection system. The frequency and the wave number of the scattered signal are analyzed. The results suggest that a broad band low frequency (several tens to several hundreds kHz) density fluctuation is excited in the CHS plasma only during neutral beam injection (NBI) or ion cyclotron resonance (ICR) heating.
Document Type: Research Article
Affiliations: 1: Research Center for Development of Far-Infrared Region, Fukui University, Bunkyo 3-9-1, Fukui 910-8507, Japan 2: National Institute for Fusion Science, Oroshi-cho, Toki-shi 509-5292, Japan
Publication date: November 1, 2004