No Li No Li 47 mg 5 mg/s 10 mg/s

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 shots have some scientific merit Observed significant decrease in D  and ELMs Timing and location of deposition appeared to be important XP-828 Initial Results and Observations

Extra Slides

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

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

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

RMS Voltage (Volts) Mass Flux (mg/s) Lithium Particle Flux is an Approximately Linear Function of Resonant Voltage Applied to the Piezoelectric Membrane

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

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

Time (s) RMS Voltage (Volts) Scattered Laser Signal (A.U.) 6 mg/s Arbitrary Waveform: Ramp-Down (8 Volts Max) Same Laser Scattering Saturation Observed

RMS Voltage (Volts) Time (s) Scattered Laser Signal (A.U.) 6 mg/s An Arbitary Waveform: With Some Modifications Might “Tweek” ELMS

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

The Two Plasmas to be Used in XP

XP828 Shot No. Dropper mg/s (Max) Temporal Profile Total Lithium (mg) HeGDC (min) Ref #10N/A06 Ref #20N/A06 Ref #30N/A06 13A26 26A66 312A or TBDA or TBDB or TBDB or TBDB or TBDB or TBDC or TBDC or TBDC TBD TBD TBD TBD

Plasma Current Time (sec) Li Flux 01 Pre-programmed Flux Profile Must be Injected ~ 450 ms Before Plasma Breakdown 450 ms

NewDiff 1.05FitX_v() 80VoltX_v 

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

Velocity at SOL = 4.5 m/sec Powder Injector

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

100  m Resonating Piezoelectric Disk SLMP Li Powder  Resonant Levitation = ± 0.5 mm ~ 5 lbs

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

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

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

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

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

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