Trilateral Euregio Cluster
Simultaneous observation of CD and C2 in the near UV region in the JET divertor
• spectral window for the observation of CD and C2
• examplesa) 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
Trilateral Euregio Cluster
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
Trilateral Euregio Cluster
C2 and CD spectroscopy in the near UV
C2 spectrum CD spectrum
observed and identified at JET (10/2003)
KT3A outer divertor ch2
Trilateral Euregio Cluster
example: N2 seeding
CNC2
Identification of CN radicals
Trilateral Euregio Cluster
example: Ar seeded plasmas
strike point on the outer horizontal target plate (14 MW NBI)
with Argon
without Argon
C2
C2CD
CD
Trilateral Euregio Cluster
example: Ar seeded plasmas
strike point on the outer horizontal target plate (14 MW NBI)
with Argon
without Argon
C2
C2
CD
CD
influence of Ar on the local plasma parameters?
Trilateral Euregio Cluster
example: high triangular plasmas
strike point on the outer horizontal target plate
different behaviour
of CD and C2
observationalong the
outer verticaltarget plate
high power: 14 MW NBI
Trilateral Euregio Cluster
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