1. Leblanc_03Feb09_1 MPTS Phase 4 Benoit P. LeBlanc PPPL 19 June 2009

2. Leblanc_03Feb09_2 Outline Scope of work for Phase 4 Technical issues Seven unused fiber bundles Gradient location database Previous inputs A partial suggestion

3. Leblanc_03Feb09_3 Scope of Phase 4 and More Install 10 – possibly 12 -- new radial channels –Use 6-filter polychromator – as in phases 1 & 2 Install two new alignment channels Rebuild phase-3 polychromators –Add 1064-nm filter for Rayleigh noise rejection (unlikely) Repair MPTS hardware – three items Calibrate 40-channel system –Spectral, fast/slow, gain; before Rayleigh/Raman Preparation work for high-Te channels –To be implemented in NSTX-U – 10keV (on the back burner)

4. Leblanc_03Feb09_4 Technical Issues Plan is to complete more of existing hardware –7 unused fiber – one bundles sees RF NB –16 unused sample-and-hold slots –Changes will occur in the polychromator room Develop a technique to unglue output end of fiber bundles – tricky but feasible Reroute a large number of fiber bundles –Split bundles need to be physical close – order of 6” –Long sequence of activities, which cannot be stopped before MPTS is back online ≥ 5 months Upgrade includes the construction of a fourth polychromator “tower” All new polychromators and ancillary hardware need to be ready at the end of FY10 experimental run Massive calibration work following successful hardware installation

5. Leblanc_03Feb09_5 Polychromator Stacked in Towers Current 3 “tower” each house 10 polychromators Each polychromator is attached to a movable shelf –Split bundles need to be next to each other vertically The fourth tower will have 12 shelves

6. Leblanc_03Feb09_6 Seven fiber bundles remain unused Seven unused bundles indicated in green R= 31.8, 86.4, 96.3, 104.9, 112.5, 154.6, 157.7 cm

7. Leblanc_03Feb09_7 Gradient location database 1446 shots from 2008 Use spline T e and n e profiles to compute the location of maximum gradients, average over times 0.15s – 0.9*max(ts_time) Database includes 29 shots suggested by Rajesh Maingi Use this data to identify new channel locations

8. Leblanc_03Feb09_8 Location of  T e vs. location of  n e Distribution plot

9. Leblanc_03Feb09_9 Location of  T e vs. location of  n e Distribution plot redux Shots suggested by R. Maingi

10. Leblanc_03Feb09_10 Location of  T e vs. location of  n e 2D histogram plot

11. Leblanc_03Feb09_11 Histogram of  T e location 3 1 2 split bundle unused Phase 1 Phase 2 Phase 3 Unused

12. Leblanc_03Feb09_12 Histogram of  n e location 3 1 2 split bundle unused Phase 1 Phase 2 Phase 3 Unused

13. Leblanc_03Feb09_13 Comments for Team Rajesh Maingi –To better resolve the H-mode pedestal gradients, I suggested the spatial resolution be optimized from ~R=141-147cm. Practically this means adding 4-5 channels. –Shell works best with smaller gap Jon Menard –I am concerned about LLD being successful in increasing D pumping –and forcing us to run larger outer gaps to reduce metal influx –What range of outer gaps would the proposals below support?, i.e. –have good gradient resolution for H-mode for our typical profiles. –Some of our transport barrier shots are clearly under-resolved in –the core, so this might warrant some additional coverage there. –Crudely, I tend to think resolving the edge is 2-3x more important –than the core programmatically Joel Hosea –Good documentation of pedestal foot, re ELMS Ben LeBlanc –The outermost bundle “sees” the BN limiter – antenna was moved inward in 2004 –The bundle will not be instrumented at this time.

14. Leblanc_03Feb09_14 Use Existing Data to Estimate Error Found among 2008 shots six pairs of successive plasmas: (S217 open & S218 open), followed by (S217 open & S218 Shut) Check shots for similar time evolution etc. Took data between 0.05s and 0.5s -- avoid saturation Compare data with both shutters open – Tef0, dTef0, nef0 – with data with one shutter closed – Tef1, dTef1, nef1 Select radial positions with raw signal (S218 shot/open) of 0.3 or 0.5.

15. Leblanc_03Feb09_15 Fiber Bundle divided in Two

16. Leblanc_03Feb09_16 Fiber Bundle divided in Three

17. Leblanc_03Feb09_17 A Suggestion… Revision June 2009 Propose 10 new channels, but will aim at 12 –Cannot fit more channels in the schedule One new radial channels at R=154.6 cm (unused FB) One new radial channels at R=31.8 cm (unused FB) Four to six(?) new radial channels in “pedestal” region –Done by splitting instrumented bundles in two No unused bundles available –Location of higher-resolution channels to be chosen by team/experts’ recommendation 2008 data suggest centering around 141 cm –How far in before splitting bundles is no longer useful Four to six in the core and ITB region –Four unused bundles in the core region

18. Leblanc_03Feb09_18 Edge Pedestal Density Phase 1 Phase 2 Phase 3 Unused

19. Leblanc_03Feb09_19 T e ITB Profile Phase 1 Phase 2 Phase 3 Unused