1. Trilateral Euregio Cluster 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 c) high triangular plasmas – different behaviour of CD and C 2 S. Brezinsek, A. Pospieszczyk A. Meigs, M. Stamp

2. Trilateral Euregio Cluster Standard CD and C 2 spectroscopy sources, particle fluxes, chemical erosion yield … observation of CD at 431 nm (A-X band) observation of C 2 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 C 2 good spectral resolution good spatial resolution and the same l-o-s good time resolution

3. Trilateral Euregio Cluster C 2 and CD spectroscopy in the near UV C 2 spectrum CD spectrum observed and identified at JET (10/2003) KT3A outer divertor ch2

4. Trilateral Euregio Cluster example: N 2 seeding CN C2C2 Identification of CN radicals

5. Trilateral Euregio Cluster example: Ar seeded plasmas strike point on the outer horizontal target plate (14 MW NBI) with Argon without Argon C2C2 C2C2 CD

6. Trilateral Euregio Cluster example: Ar seeded plasmas strike point on the outer horizontal target plate (14 MW NBI) with Argon without Argon C2C2 C2C2 CD influence of Ar on the local plasma parameters?

7. Trilateral Euregio Cluster example: high triangular plasmas strike point on the outer horizontal target plate different behaviour of CD and C 2 observation along the outer vertical target plate high power: 14 MW NBI

8. Trilateral Euregio Cluster conclusion spectral region is good for the observation of relative changes of CD and C 2 KT3A system in combination with this spectral range very useful (time / spatial resolution) only theoretical data for CD (B-X) transition available

9. Trilateral Euregio Cluster KT3 observation system