No Li

1. No Li 47 mg 5 mg/s 10 mg/s 130374 130386 130388 130389 No Li

5. XP-828 Initial Results and Observations • All eleven shots technically successful – small timing problem • Ramp-ups and square wave temporal profiles employed • Rates from 1 mg/s to ~ 35 mg/s employed • NSTX much more tolerant of Li powder than expected • Total of 82 mg injected during 11 shots • Not a great day for NSTX reproducibility or documentation • 3 - 5 shots have some scientific merit • Observed significant decrease in Da and ELMs • Timing and location of deposition appeared to be important

6. Extra Slides

8. Prototype Acoustic Resonance Dropper Can Drop from 0.3 mg up to Much-Too-Much Powder (Li Surrogate) Powder Injector Velocity at SOL = 4.5 m/sec

9. Existing Computerized Laboratory Test Facility Drop Chamber Laser Scattering Module to Vac Pump to Vac Pump 2 ¾ Gate Valve Bracing ½ O.D. Stainless Tubing 1.0 m Glass Funnel w Long Stem Pyrex Tube 2 ½ O.D.

10. New Umbrella Throttle Seems to Work More Reliably Than Old Simple Throttle Design – Higher Fluxes Simple Throttle Umbrella Throttle Li Powder Li Powder Higher Reliable Particle Flow (~ 3 mg/s)

11. Lithium Particle Flux is an Approximately Linear Function of Resonant Voltage Applied to the Piezoelectric Membrane 14 12 10 8 Mass Flux (mg/s) 6 4 2 0 0 2 4 6 8 10 12 14 16 RMS Voltage (Volts)

12. Laser Scattered Signal Reproducibility is Fairly Good However, Signal Saturates at 2 - 4 mg/s (3 - 5 Vrms) 8.0 V: 5.8 mg/s 3.0 V: 2.2 mg/s 2.0 V: 1.5 mg/s Scattered Laser Signal (A.U.) 1.0 V: 0.7 mg/s 0.5 V: 0.4 mg/s 0 1 2 3 4 5 6 7 Time (s)

13. Two Arbitrary Waveforms: Ramp-Ups (4 & 8 Volts Max) Laser Scattered Signal Saturates at 2 - 4 mg/s (3 - 5 Vrms) 8 6 mg/s 6 4 3mg/s Scattered Laser Signal (A.U.) RMS Voltage (Volts) 2 0 0 0.4 0.6 0.8 1.0 0.2 Time (s)

14. Arbitrary Waveform: Ramp-Down (8 Volts Max) Same Laser Scattering Saturation Observed 8 6 mg/s 6 4 Scattered Laser Signal (A.U.) RMS Voltage (Volts) 2 0 0 0.4 0.6 0.8 1.0 0.2 Time (s)

15. An Arbitary Waveform: With Some Modifications Might “Tweek” ELMS 12 8 6 mg/s 4 RMS Voltage (Volts) 0 Scattered Laser Signal (A.U.) 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 Time (s)

16. “Early” Li Can be Preferentially Directed to Lower Divertor Small Plasma Initiated on the Center Stack Flux Plot Shown Just After Breakdown Pre-Pulse of Lithium for 50 ms (~ 100 Oscillations) 850 ms Before Breakdown

17. The Two Plasmas to be Used in XP 828 129019 129059

20. Pre-programmed Flux Profile Must be Injected ~ 450 ms Before Plasma Breakdown Li Flux 450 ms Plasma Current 0 1 Time (sec)

21. 0.06 0.05 0.04 NewDiff 0.03 1.05 Fit ( X_v ) 0.02 0.01 0 0 0 1 2 3 4 5 6 7 8 0 Volt , X_v 8

22. 14 12 10 8 6 4 2 0 0 2 4 6 8 10 12 14 16

23. Purpose : Study ELM Suppression by in situ Modification of NSTX Plasma Surface Interaction: Li on Graphite Lithium Evaporators with Shutters R/a = 1.46 BT = 0.5 T Ip = 800 kA PNBI = 4 MW Lower Single Null Type 1 ELMS B treated Graphite H. Kugel P2-58 2

31. Powder Injector Velocity at SOL = 4.5 m/sec

32. Dropper by Acoustic Resonance Horizontal Injection by PZT Fan Vertical Injection by Acoustic Resonance

33. 100 mm Resonant Levitation ~ ~ Resonant Dropping SLMP Li Powder = ± 0.5 mm ~ 5 lbs Resonating Piezoelectric Disk

34. Modes of the Vibrating Piezoelectric Drumhead 0,2 Mode 2 kHz 0,1 Mode 290 Hz 0,3 Mode

35. 0,2 Mode of Piezoelectric Disk with Glass Beads – 2 KHz

36. 0,2 Node of Piezoelectric Disk with Glass Beads – 2 KHz

37. Fixed Level Inside Node Throttle: ¼ - 28 Screw N.B. 30mil Gap: 15 particles high 20 particles wide O-Ring 30 mil 100 mil g Piezoelectric Membrane (0,2) Node 100 - 300 mg/s 3.5 mg/s 0.3 mg/s Scale 20:1

38. Resonant Levitation ~ ~ Resonant Dropping Dusting of Glass Spheres Levitated from Center of Mode (0,2) Mode 25 mm Throttle used to force Particles to drop through Hole in piezo membrane Resonating Piezoelectric Disk

39. Dropper by Acoustic Resonance Horizontal Injection by PZT Fan (or by Rotating Wheel) Vertical Injection by Acoustic Resonance