n seeding at high triangularity and low q95 report about spectroscopy of #62565

Trilateral Euregio Cluster

Observation of CN molecules in nitrogen seeded plasmasS. Brezinsek, A. Meigs, A. Pospieszczyk, M. Stamp,

J. Rapp

N Seeding at High Triangularity and Low q95Report about spectroscopy of #62565

Original aim: Test of spectrometer set-up for H-C measurements

fortunate: GIM 11 -> GIM 10

GIM11

GIM10

N2 blow

Trilateral Euregio Cluster

Spectral regions and line of sights

Spectral region around 391 nm with KT3A – very good choice

GIM10

Trilateral Euregio Cluster

Spatial & temporal discriminations for N+

N+ appears during N2 blow and mainly near separatrix

Trilateral Euregio Cluster

Spectral ranges for nitrogen and its molecular compounds

Overlap with CD (A-X)

Trilateral Euregio Cluster

N2+ spectroscopy on TEXTOR

TEXTOR: N2+ spectra could be well identified (gas blow)

JET: None of these could be found so far

Trilateral Euregio Cluster

Appearance of CN during N2 blow

2 spectra at different times difference spectrum (larger view)

CN bands appear only directly at the wallnitrogen and oxygen remain also on inner viewing lines

Trilateral Euregio Cluster

Spatial & temporal discrimination for CN

CN appears during N2 blow and near the wall only

Trilateral Euregio Cluster

Results & questions

Only CN and N+ could be found

No traces of N2+ and N2

+ in the high resolution wavelength bands

No specific effects on C or hydrocarbons so far (might appear with higher blow rates)

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Will the CN be formed in the bulk and released by (chemical) sputtering?

Formation of DCN or does it come from DCN?

Is the N codeposited?

What happens to the CN ?

Are there beneficial effects from CN formation

-> removal of C-layers