A four array ECEI instrument for imagin and visualization of MHD and microturbulence phenomena on the KSTAR tokamak

Summary form only given. An innovative, four array electron cyclotron emission (ECE) imaging (ECEI) system is under development for use on the KSTAR tokamak. ECEI is a passive radiometric imaging diagnostic technique in which broadband ECE radiation is collected by a 1-D imaging array to generate 2-D localized, time-resolved electron temperature Te images. Translatable optics allow each array to independently focus on different portions of the KSTAR plasma, forming 20 (v) times 8 (h) = 128 channel images of Te profiles and fluctuations. The KSTAR system consists of two ECEI instruments on widely separated toroidal locations. Each instrument is itself comprised of a pair of imaging arrays which view the plasma through a single midplane port (see below), with a quasi-optical beamsplitter to separate the high field side (HFS) and low field side (LFS) signals. Unique to this design is the placement of large aperture optics within the KSTAR cassette, which maximizes the plasma coverage that can be achieved. The HFS system can be focused at any normalized radius from -0.7 les r/a les +0.2, with a vertical coverage that can be extended to > 50 cm. The LFS system focus can likewise be varied from +0.1 les r/a les +0.9, with a vertical coverage as large as > 45 cm. The ECEI instrument is scheduled for installation on the KSTAR tokamak in early 2010. ECEI will be employed in a wide range of physics studies, but will focus on unraveling the magnetic reconnection physics associated with the sawtooth oscillation.