1. Development and Analysis of Gas Puff CXRS in SOL
Motivation
Develop an alternative edge rotation measurement:
Inner wall measurement
Alternative to beam CXRS
Confirm probe flow measurements
Potentially used to determine flow shear and electric field profile
H-mode and momentum transport studies
Current status:
He gas puff used for ‘cross-beam’ measurement of HeII at inner wall
He ions appear to not equilibrate before being completely ionized
Leads to velocity measurements that appear too low
Leads to unreliable temperature measurements
Trends based on probe measurements confirmed but differences in flow magnitude and direction leads to the belief that the He puff is locally perturbative

2. BV CXRS measurement looks promising
Current status (continued):
BV CXRS also done at the inner wall with gas puff for ‘neutral beam’
B+5 ions at ~ separatrix sampled and Ti ~ 80 eV (so it appears they are well-equilibrated)
Few measurements and don’t know the limits of its use (how far inside the separatrix, density range…)

3. Development and Analysis of Gas Puff CXRS in SOL
Experiments:
Vary plasma density
By varying the density we can explore the limits and dependence of the rotation measurement on density. We can also test the range of puff duration so as not to perturb the local plasma density, but still localize emission.
Vary the location of the innermost viewing chord in the plasma to identify how far inside the separatrix that this technique gives a decent signal.
BV emission becomes significant near the separatrix (~50 eV) and presumably further into the core. By varying the size of the inner gap we can build up a profile both across our fibers as well as into the plasma. We will explore the limitation of neutral penetration from the puff into the plasma pedestal region.
Expectations:
Analysis to determine if further implementation is warranted
New spectrometer for better resolution?
Additional views at the outside edge?
Poloidal measurements for electric field analysis?