1. J. Boedo, UCSD Fast Probe Results and Plans By J. Boedo For the UCSD and NSTX Teams

2. J. Boedo, UCSD Probe Installed and Commissioned 11 deg angle 6.8” Location is 6/8” below midplane

3. J. Boedo, UCSD New head and tips to accommodate curvature and heat flux Thermal Conductivity Thermalgraph Tips (parallel) 800 W/mK Copper401 W/mK POCO graphite72 W/mK

4. J. Boedo, UCSD Isat Vf1 Vf2 Epol Double Probe Vf3 Mach1 Mach2 Er Vf4 Te fluct Existing Probe Head has 10 Tips Tips in blue will be active on day one, the rest implemented as upgrades (if funded) Fluctuations to 1 MHz Two Vf tips used for Epol (and fluctuations) Two Vf tips used as Er (and fluctuations) >> Reynolds Stress One tip as Isat >> ne Two tips as double probe (Te and Ne profiles)

5. J. Boedo, UCSD Data Taken at High Spatial and Temporal Resolution Insertion completed in 100 ms. ~30 ms in plasma Time resolution for Te and Ne is 1 ms Time resolution for fluctuations is 1 micro sec Spatial resolution is 1.5-2 mm (tip size + probe motion)

6. J. Boedo, UCSD Within the limited shot space, density and power were varied. So scaling is inconclusive So far: decreases in H mode with power 2.5>1.5 cm Will obtain wider operating space in the future and produce scalings

7. J. Boedo, UCSD H-mode Radial Electric Field Flat in SOL

8. J. Boedo, UCSD Fluctuation Quantities to Characterize in NSTX Need to add Te fluct capability

9. J. Boedo, UCSD Harmonic Diganostic 250 W RF amp Pearson coil Probe Amp R1 V_ fast V II f drive = 400 kHz Amp 400 kHz Bandpass filter 800 kHz Bandpass filter Ampli- tude detector I2I2 I_ fast T e _slow Tunable LPF Compa- rator Analog multiplier Analog divider Ampli- tude detector Ampli- tude detector I  /I 2  Amp Analog multiplier Compa- rator Adder Ref V_min I_min Dummy transmission line R2 C3 C1 C2

10. J. Boedo, UCSD Harmonics Technique Current to a DC-floating probe driven by sinusoidal voltage can be expressed as a series of sinusoidal harmonics [1] : where - amplitude of m th harmonic - Bessel functions of integer order k For eU 0 /kT e << 1: Thus T e can be determined from the ratio of the amplitudes of 1 st and 2 nd harmonics The error of this approximation for eU 0 /kT e = 1 is only about 5% [1] [1] Boedo et al, Rev. Sci. Instrum. 70 (1999), 2997

11. J. Boedo, UCSD Need to Include Magnetic component Particle Flux Reynolds Stress (neglecting ion pressure fluctuations) Heat Flux Parallel Current Flux Helicity Flux

12. J. Boedo, UCSD Normalized N fluctuations very large

13. J. Boedo, UCSD Radial Turbulent Flux Lower in H-mode Value is ~3-5 10 17 cm-2 s-1

14. J. Boedo, UCSD Intermittent Plasma Events Pervasive

15. J. Boedo, UCSD Power Spectrum Comparison Power spectrum vs f (in kHz) from probe data during gas injection (solid circles) and without(x) and comparison to that obtained form the GPI system (open circles). Note that the power spans y 4 orders of magnitude indicating excellent S/N ratio.

16. J. Boedo, UCSD Intermittency (Radial Convective Transport) Lower in H-Mode L-Mode 109033 H-Mode 109052 Intermittency is very strong in NSTX!

17. J. Boedo, UCSD Intermittency (Radial Convective Transport) Lower in H-Mode L-Mode 109033 H-Mode 109052 Intermittency is very strong in NSTX!

18. J. Boedo, UCSD L-Mode 109033 Density is highly intermittent Rate of bursts is ~1E4 Poloidal field is much less intermittent Coherent modes show in Etheta Instantaneous flux is 1-3E15 cm-2s-1

19. J. Boedo, UCSD H-Mode 109052 Density is intermittent (ELMs?) Rate of bursts is 2E3 Poloidal field is much less intermittent Coherent modes show in Etheta Instantaneous flux is ~2E15 cm-2s-1

20. J. Boedo, UCSD Initial Reynolds Stress and Bicoherency Measurements Codes Written and Tested H-Mode L-Mode

21. J. Boedo, UCSD Bispectrum H-modeL-Mode f3=f1+f2 f3=f1-f2

22. J. Boedo, UCSD Bicoherency H-modeL-Mode

23. J. Boedo, UCSD Profile Conclusions Edge/SOL profiles available with high spatial (2-2.5 mm) resolution Limited to 1086xx, 1089xx, 109032-109062 Fully calibrated data for 109032-xxx062 NSTX profiles seem different from larger aspect ratio devices Te profile in the edge/SOL is flat at 25-30 eV Ne profile has a very long decay length. Reduced by power! H-mode Er profile flat in SOL How do flat Te profiles are maintained? Do we have (more) anomalous radial transport? (intermittency) Adding fast Te diagnostic

24. J. Boedo, UCSD Future Work and Goals Data obtained in L and H-mode. SOL length scales with power. Ongoing Many puzzles need addressing Features usually associated with LCFS vicinity are different in NSTX, such as a potential well, steep H-mode profiles, etc Ongoing Intermittency is quite strong in NSTX (very strong radial transport?) Need to quantify electrostatic turbulence and Intermittency (enough to explain strong transport?) Codes just ported for electrostatic turbulence, ongoing for intermittency! Bicoherency and Reynolds Stress codes just finished. Investigate energy cascading and self-organized flows Need to quantify electromagnetic components of transport Upgraded head partially designed and to be built in FY04

25. J. Boedo, UCSD