XP #802 - Biased Electrodes
This presentation is the property of its rightful owner.
Sponsored Links
1 / 6

XP #802 - Biased Electrodes PowerPoint PPT Presentation


  • 40 Views
  • Uploaded on
  • Presentation posted in: General

XP #802 - Biased Electrodes. S.J. Zweben, R.J. Maqueda, L. Roquemore, R.J. Marsala, Y. Raitses, R. Kaita, C. Bush R.H. Cohen, D.D. Ryutov, M. Umansky (LLNL). • Upgrades for 2008 • Physics goals for 2008 • Proposal for 2008 • Possible concerns. Team XP review 1/11/08.

Download Presentation

XP #802 - Biased Electrodes

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Xp 802 biased electrodes

XP #802 - Biased Electrodes

S.J. Zweben, R.J. Maqueda, L. Roquemore,

R.J. Marsala, Y. Raitses, R. Kaita, C. Bush

R.H. Cohen, D.D. Ryutov, M. Umansky (LLNL)

• Upgrades for 2008

• Physics goals for 2008

• Proposal for 2008

• Possible concerns

Team XP review 1/11/08


Xp 802 biased electrodes

Hardware Upgrades for 2008

• Two positive supplies increased from ~10 A to ~30 A

• Added radial array of probes to measure local SOL

• Will now have fast camera views of BEaP electrodes

radial

probe

array

GPI

puffer

B

cable

shield

BEaP


Xp 802 biased electrodes

BEaP Goals for 2008

• Measure effect of increased positive bias (x3 in I, x2 in V)

• Measure effect on local SOL with new radial probe array

• View effects of biasing on D light near BEaP electrodes

• Evaluate effect of double-probe biasing (floating electrodes)

• Evaluate effects during NBI and RF (via piggy-backing ?)


Xp 802 biased electrodes

BEaP XP for 2008 (~1/2 day)

Repeat #124688, I=0.8 MA, B=4.5 T, outer gap ~5 cm -> 1 cm

1st hour: single-electrode voltage scan up to +100 V (≤ 30 A)

monitor local array, local D light at BEaP, GPI images

look for effects on plasma (impurities, radiation, divertor)

after this, check probe-GPI correlations for alignment

2nd hour: optimize alignment based on shots #1-5 (i.e. adjust Ip)

try four electrode biasing +/-/+/- (VExB outward at array)

3rd hour: reconfigure for double-probe biasing (pending review)

4th hour: repeat best case, or try with NBI (using ~5 cm gap)


Xp 802 biased electrodes

Approximate Shot Sequence


Xp 802 biased electrodes

Possible Concerns

• Electrode heating: P(2008) ≤ 3 kW @ 50% for 0.2 sec

=> maximum T (surface) ~ 75 ºC during shot

=> maximum T (bulk) ≤ 40 ºC after shot

=> should be no problem with melting

• Arcing: will look at electrode currents and fast camera

• Impurity influx: will monitor iron with

SPRED and Ptot with bolometer

no increase in Ptot in 2007 run

• Floating double-probe operation

with voltage transients ?

(review before implementation)


  • Login