High definition imaging in the Mega Amp Spherical Torus spherical tokamak from soft x rays to infrared (invited)

High definition imaging in the Mega Amp Spherical Torus spherical tokamak from soft x rays to infrared (invited)

High definition imaging in the Mega Amp Spherical Torus spherical tokamak from soft x rays to infrared (invited) 150 150 Mathew

High definition imaging in the Mega Amp Spherical Torus spherical tokamak from soft x rays to infrared (invited)

The Mega Amp Spherical Torus ( MAST ) diagnostic needs are strongly influenced by physics goals that often require diagnostic integration and cross-mapping, especially in fine-scale investigations, such as transport barriers. Conversely, the unrivalled viewing access to the edge, scrape-off layer ( SOL ) and divertor regions, provided by the MAST open geometry, impacts on the physics program priorities. A supporting suite diagnostics, such as the high definition Thomson scattering systems, provide considerable added value in detailed data interpretation ( e.g., bremsstrahlung emissivity in terms of Z eff ) . Thus, to exploit these advantages, an extensive set of high-resolution imaging diagnostics have been installed, encompassing soft x-rays, visible bremsstrahlung, charge exchange recognisation radiation, D a from NBI, and edge plasma neutrals, and infrared ( IR ) from the divertor and wall regions. Plasma light collection optics provide near parallel illumination of narrow bandpass interference filters to give monochromatic images. One adaptation provides multiwavelength images; another accommodates smooth variation of wavelength across an image ( e.g., for a range of Doppler shifts beam fast neutrals ) . Diagnostic synergy is enhanced by combining such diagnostics to common viewing optics which allow exact-mapping. Soft x-ray tangential imaging has been achieved by using a two dimensional charge coupled device detector in a pinhole camera. Finally, a fast IR camera monitors the power deposition on the first wall and divertor plates, important in quantifying power losses ( e.g., ELMs, disruptions ) , and complemented by visible viewing of the SOL, and linear D a cameras.

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12/10/2004