A Simultaneous Spectroscopic Measurement of the Global and Edge Local Structures in the Ion Temperature and Plasma Rotation Profiles in the Compact Helical System

Shin NISHIMURA, Ken-ichi NAGAOKA, Yasuo YOSHIMURA, Kiichiro NAKAMURA, Harukazu IGUCHI, Tsuyoshi AKIYAMA, Takashi MINAMI, Tetsutaro OISHI, Katsumi IDA, Kazuo TOI, Akihiro SHIMIZU, Mitsutaka ISOBE (+5 others)
2007 Plasma and Fusion Research  
In charge exchange spectroscopy (CXS), a simultaneous observation in different plasma toroidal cross sections and/or viewing ports is required to investigate radial distributions of ion temperatures T i (r), and poloidal rotation velocities V p (r) in magnetically confined toroidal plasmas. In recent studies of the edge transport barrier (ETB) in the Compact Helical System (CHS), a simultaneous viewing of the vertically elongated and the horizontally elongated plasma cross sections is used to
more » ... ctions is used to improve the spatial resolution at the edge region. The 90 fibers used for this purpose are connected to one spectrometer, and a 256 × 243 pixel sampling CCD is used to detect the diffraction image. It is found that there is a localized edge ion temperature pedestal region with ∆T i ≈ 100 eV and ∆r/a ≈ 0.1, where r and a are flux surface averaged minor radii of measured surfaces and the outermost flux surface, respectively. The negative radial electric field at the edge is increased in the high confinement phase because of the increased ion pressure.
doi:10.1585/pfr.2.037 fatcat:6z7ni45m6vb6nmohookc3rneuy