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Simultaneous observation of CD and C 2 in the near UV region in the JET divertor. spectral window for the observation of CD and C 2 examples a) nitrogen seeding – observation of CN (last week) b) argon seeding – reduction of CD and C 2 light
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Simultaneous observation of CD and C2in the near UV region in the JET divertor • spectral window for the observation of CD and C2 • examples a) nitrogen seeding – observation of CN (last week) b) argon seeding – reduction of CD and C2 light c) high triangular plasmas – different behaviour of CD and C2 S. Brezinsek, A. Pospieszczyk A. Meigs, M. Stamp
Standard CD and C2 spectroscopy • sources, particle fluxes, chemical erosion yield … • observation of CD at 431 nm (A-X band) • observation of C2 at 517 nm (Swan band) • wide range & low resolution (e.g. KS3) • different devices & l-o-s (e.g. KT3) • good resolution & low time resolution (e.g. KME) often necessary: simultaneous measurement of CD and C2 • good spectral resolution • good spatial resolution and the same l-o-s • good time resolution
C2 and CD spectroscopy in the near UV C2 spectrum CD spectrum observed and identified at JET (10/2003) KT3A outer divertor ch2
example: N2 seeding Identification of CN radicals C2 CN
example: Ar seeded plasmas strike point on the outer horizontal target plate (14 MW NBI) without Argon CD C2 with Argon C2 CD
example: Ar seeded plasmas strike point on the outer horizontal target plate (14 MW NBI) without Argon CD C2 influence of Ar on the local plasma parameters? with Argon CD C2
example: high triangular plasmas strike point on the outer horizontal target plate high power: 14 MW NBI observation along the outer vertical target plate different behaviour of CD and C2
conclusion • spectral region is good for the observation of relative changes of CD and C2 • KT3A system in combination with this spectral range very useful (time / spatial resolution) • only theoretical data for CD (B-X) transition available