1. Flows, Turbulence, and the Edge Plasma in NSTX C.E. Bush, S. Zweben, R. Maqueda, W. Davis, D. Johnson, R. Kaita, H. Kugel, L. Roquemore, G. Wurden and the NSTX Team NSTX 2004 Results Review, Sept. 20-21 XP442 - Scoping Study of Ohmic H-modes Fast Cameras - Flows, turbulence, and phenomena Tile Langmuir Probes

2. C.Bush, Results/Forum 2004 Page 2 Motivation Ohmic H-modes have low centrally peaked densities – Explore edge and core turbulence simultaneously – Target plasma for early NBI and combined ITB and ETB NBIOH ELM- Free OH ELMy

3. C.Bush, Results/Forum 2004 Page 3 Goals Scoping study in parameter/configuration space Measure turbulence in core and edge of H- mode simultaneously Assess use as Target Plasma

4. C.Bush, Results/Forum 2004 Page 4 Results for Ohmic H-mode Scoping Study One-half run day – mini-scans in B t and I p – Some OH-H-modes randomly on other days H-modes at 600 to 900 kA, 3.0 to 4.5 kG TF – Short H-mode at I p = 600 kA, B t = 3 kG OH H-modes obtained for 1 st time ever on NSTX during this run – Most readily obtained after hot boronization – Alternating helium conditioning shots seem to help – Obtained both double null (DN) and lower single null (LSN) divertor – Most short duration, some with ELMs and some ELM-free Peaked Central n e – ELMy: Small high frequency ELMs (?) keep ears from developing – ELM-free: have ears, but edge peak lower than central n e No turbulence measurements made in core of OH H-mode Some edge reflectometer fluctuation data; Some GPI data, not L-H

5. C.Bush, Results/Forum 2004 Page 5 PLOSS for NBI and OH Hmodes

6. C.Bush, Results/Forum 2004 Page 6 Edge measurements (ERD) in Ohmic H-modes show E r and V p change prior to L-H transition E r and V p begin to change 10 to 20 ms before L-H transition (here at t ~ 0.220 sec) H-mode Shot 113350 Time (s) V p (km/s) V T (km/s) E r (kV/m) I p (MA) 0.160.20 0.24 0.28 1.0 0.8 0.4 0.0 -0.5 -10 5 0 -5 -1.5 -2.0 -2.5 -15 5 0 -10 -15 -5

7. C.Bush, Results/Forum 2004 Page 7 Highest Normalized    Shot: Perturbed by an External Kink Mode: (CIII filter) Shot 114463

8. C.Bush, Results/Forum 2004 Page 8 H-mode Showing Quiescent  External Kink  Small Torus at EOS: (CIII filter) Shot 114151

9. C.Bush, Results/Forum 2004 Page 9 #113484 @ 4 µsec/frame (D  light) Medium ELM Images #2

10. C.Bush, Results/Forum 2004 Page 10 Activity Near Inner Wall During and Following an ELM (157-175 ms) Shot 113862 Magnetic field line plot from EFIT

11. C.Bush, Results/Forum 2004 Page 11 Langmuir Probes Flush mounted single probes Total of 22 probes, 6 top and 6 bottom divertors – Remainder along centerstack Have data for vast majority of shots Virtually no signal from centerstack probes when plasma is diverted Some I sat, T e, n e data in Tree soon Tile Langmuir Probes

12. C.Bush, Results/Forum 2004 Page 12 Future Plans Continue XP442 – Get core turbulence data – Finish scoping studies Fast camera studies – Add filters – CI, LiII, Neon – Correct fisheye distortion Langmuir Probes – Get data in tree – Additional probes (?)

13. Backup Slides Extras

14. C.Bush, Results/Forum 2004 Page 14 Ion Saturation Current vs. Time 0.12 0.08 0.04 0.00 0.100.200.300.40 0.08 0.04 0.00 0.100.200.300.40 112830, Smoothed over 2 sweeps Raw isat data I sat Time [s]

15. C.Bush, Results/Forum 2004 Page 15 Activity Near Inner Wall During an ELM (160 ms) Shot 113862 From EFIT