Alcator C-Mod Run 1060720 Information

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Miniproposals
Miniproposal:455
Date Filed: 5/26/2006
Title:Determination of LHCD efficiency
First Author:J. Randall Wilson
Session Leader:J. Randall Wilson (shots 1-29)

Operators
Session leader(s):J. Randall Wilson
Physics operator(s):Ron Parker
Engineering operator(s):Bill Cochran,Ed Fitzgerald,Gary Dekow

Engineering Operator Run Comment
MP#418 LH System Conditioning

Session Leader Plans
Entered: Jul 19 2006 05:12:59:317PM
Author: J. Randall Wilson
Run Plan

3 goals

1. Complete phase scan at ~ 500+ kW 60 , 90 120

2. Increase injected power to near 1 MW look for full CD

3. Couple power during current ramp (begin AT scenario study)

Physics Operators Plans
Entered: Jul 19 2006 04:48:07:260PM
Author: Ron Parker
Physop Plan and Engineering Setup Thursday, July 20, 2006

MP#418 LH System Conditioning
SL: Wilson
PO: Parker

ECDC from 6:00 - 8:00 AM in D2 at 2.e-4 Torr

Power systems as on 1060615
A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and enabled.
C-coil Start=0.3sec, Invert=2.0sec

No ICRF Required for this run.

Gas Setup:
----------
fill B-top 6psi D2 Hybrid enabled (PG4)
fill B-side lower 1 psi Argon Hybrid Disabled (PG1)
fill B-side Upper as is, Hybrid Disabled (PG2)
fill B-main 40psi D2 Hybrid Enabled (PG3)


Enable ECE, VUV, Z-bolo shutter assuming no vacuum problems

Run Plan: Setup nominal diverted L-Mode discharge. BT = 5.4 T
IP = 700 kA, nl_04 ~ 0.4e20 m-2. 60, 90, 120 deg phase scan @ ~ 500 kW
net LH power. Then, raise power toward 1 MW -- try for full LH current drive
at lower current.

Session Leader Summaries
Entered: Jul 20 2006 05:24:40:230PM
Author: J. Randall Wilson
Took shots at 60, 90 and 120 degree phasing for non-thermal emission scan

raised power at 60 degree phasing (had least problems with trips due to intrinsic reflection)

Power levels up to ~800 kW injected

loop voltages as low as 0.2 V achieved

pulse lengths up to 0.6 s

Physics Operator Summaries
Entered: Jul 20 2006 05:21:05:620PM
Author: Ron Parker
A good run for lower hybrid. Machine ran flawlessly, no fizzles, no duds and no disruptions! Lower hybrid also performed well, reaching 800 kW in sustained pulses. Loop voltages as low as 0.2 Volts were obtained at 700 kA. All in all, a good day.

Scorecard: 29 shots, no duds, no fizzles, no disruptions.

Session Leader Comments
Jul 20 2006 09:20:38:247AM1060720001J. Randall WilsonFirst shot at 60 degrees 500 kW lloks good

density a little high and more density rise than usual

may need to push in a little
Jul 20 2006 09:28:00:860AM1060720002J. Randall Wilsonsame power, phase

density a little lower density rise less, ECE emission larger
Jul 20 2006 09:41:33:677AM1060720003J. Randall Wilsonraise power to 90 kW each klystron

pulse short arc

density a little low
Jul 20 2006 10:29:07:180AM1060720004J. Randall Wilsonraise power to 90 kW each klystron

good pulse at almost 600 kW injected

density good
Jul 20 2006 10:29:44:740AM1060720005J. Randall Wilsonchnage phase to 120 degrees

lower power

density low multiple trips
Jul 20 2006 10:42:03:463AM1060720006J. Randall Wilsonstill trips due to high reflection on 6B andf 13B

probably need more density to lower reflection at this phase
Jul 20 2006 11:16:11:743AM1060720008J. Randall Wilsonpushed coupler in helped got some pulse width
Jul 20 2006 11:43:24:020AM1060720009J. Randall Wilsonreal arc on klystron 2 in jungle gym between 3/4 split but before up/down split
Jul 20 2006 12:23:33:160PM1060720011J. Randall Wilsongo back to 90 and push power

ramp to 100 kW per klystron good
Jul 20 2006 12:46:02:997PM1060720012J. Randall Wilsongo back to 90 and push power

ramp for 0.3 s then flat

flat didn't work
Jul 20 2006 12:59:11:533PM1060720013J. Randall Wilsongo back to 90 and push power

ramp for 0.3 s then flat

flat worked
Jul 20 2006 02:38:29:007PM1060720016J. Randall Wilson710 MW
Jul 20 2006 02:38:48:180PM1060720018J. Randall Wilsonjust too much inherent reflection
Jul 20 2006 03:21:22:777PM1060720020J. Randall Wilsonup near 800 kW
Jul 20 2006 03:22:02:760PM1060720021J. Randall Wilsonmany dropouts with no reasons
Jul 20 2006 03:25:05:307PM1060720022J. Randall Wilsonlower power to 490 kW max

fine no trips
Jul 20 2006 03:42:00:813PM1060720023J. Randall Wilsonraise density and move out

raises reflection
Jul 20 2006 03:56:38:710PM1060720024J. Randall Wilsonlower density

better
Jul 20 2006 04:05:57:700PM1060720025J. Randall Wilsonextend flat-top by 0.2 s
Jul 20 2006 04:18:06:250PM1060720026J. Randall Wilsonramp power from 60 to 100 kW perklystron then 0.3 s flat at 100 kW
Jul 20 2006 04:40:00:717PM1060720027J. Randall Wilsonramp power from 60 to 110 kW per klystron then 0.3 s flat at 110 kW
Jul 20 2006 04:48:52:947PM1060720028J. Randall Wilsonramp power from 60 to 120 kW per klystron then 0.3 s flat at 120 kW
Jul 20 2006 05:13:29:807PM1060720029J. Randall Wilsoneven higher excellent shot

vloop dips to 0.2 V

750 kW during flat-top

Physics Operator Comments
Jul 20 2006 08:41:44:340AM1060720001Ron ParkerGuten Morgen.

No systems nor weather problems this morning and we should run the first shot on time.
Jul 20 2006 09:40:41:927AM1060720001Ron ParkerShot 1 ran well, Rf full pulse. Density a bit high, reduce for next shot.
Jul 20 2006 09:41:49:613AM1060720002Ron ParkerGood shot, RF full length. Density still a bit high.
Jul 20 2006 09:43:33:863AM1060720003Ron ParkerShot 3 disrupted at 0.9 s.
Jul 20 2006 10:20:12:627AM1060720004Ron ParkerShot 4 was good, RF full length. Next: 120 deg phasing.
Jul 20 2006 10:34:20:337AM1060720005Ron ParkerShot 5 ran Ok, very low density. RF triped on each restrike due to high reflections on WG 6 and 13 botoom.
Jul 20 2006 10:43:14:120AM1060720006Ron ParkerShot 6 went off OK, but LH still tripping on reflection. Increase density again to 0.4e20 m-2.
Jul 20 2006 11:44:33:520AM1060720007Ron ParkerShot 7 ran OK, no LH due to trips.
Jul 20 2006 11:45:25:990AM1060720008Ron ParkerShot 8 ran well, got LH pulse after several trips.
Jul 20 2006 11:43:23:800AM1060720009Ron ParkerShot 9 ran well, but LH tripped on every retry. Breakdown between pantleg and jg couplers fed by klystron 2?
Jul 20 2006 12:13:01:953PM1060720010Ron ParkerShot 10 ran OK, Rf tripped on all but last retry.
Jul 20 2006 12:25:36:520PM1060720011Ron ParkerShot 11 was good; RF back to 90 deg phasing, ramping from 80 - 100 kW/klystron.
Jul 20 2006 01:09:12:303PM1060720012Ron ParkerShot 12 ran OK, one trip in RF.
Jul 20 2006 01:10:11:943PM1060720013Ron ParkerShot 13 was OK, but several trips in RF near end of pulse.
Jul 20 2006 01:07:44:147PM1060720014Ron ParkerShot 14 ran well, but RF tripped several times
Jul 20 2006 01:26:53:340PM1060720015Ron ParkerShot 15 ran, but circulator arc (klystron 3) caused trip out of retries.

Design flaw?
Jul 20 2006 01:42:32:940PM1060720016Ron ParkerShot 16 was a good shot, RF had only one trip.
Jul 20 2006 01:43:19:080PM1060720017Ron ParkerShot 17 didn't go -- an OH breaker pulled.
Jul 20 2006 03:11:12:740PM1060720018Ron ParkerShot OK, no RF too many dropouts.
Jul 20 2006 02:39:15:977PM1060720019Ron ParkerGood shot, went to 60 deg phasing, one dropout. Low loop volts.
Jul 20 2006 03:09:33:957PM1060720020Ron ParkerShot 20 ran well, RF finally stayed on at ~0.86 s, power reached 800 kW.
Jul 20 2006 03:09:59:613PM1060720021Ron ParkerShot 21 had several RF dropouts.
Jul 20 2006 03:27:52:573PM1060720022Ron ParkerShot 22 was to test whether the trip system was operating correctly.

Lower power RF shot went through from beginning to end.
Jul 20 2006 03:29:10:120PM1060720022Ron ParkerFor shot 23, power will be kept low, and density increased to check dependence of reflection coefficient on density at grill.
Jul 20 2006 03:43:20:487PM1060720023Ron ParkerResult of raising the density and moving plasma out 0.5 cm was to increase reflection coefficient. Next: Lower n slightly and move plasma ~0.5 cm away from grill.
Jul 20 2006 03:56:22:913PM1060720024Ron ParkerMaybe slight improvement in reflection coefficient, not too significant.

Back to nominal conditions, shot 22. Longer flat top on RF pulse.
Jul 20 2006 04:12:06:717PM1060720025Ron ParkerNice long LH shot with good evidence of electron heating!

Next: Ramp power to higher level.
Jul 20 2006 04:39:23:737PM1060720027Ron ParkerShot 27 went off OK. RF had one dropout near end.
Jul 20 2006 04:40:05:497PM1060720027Ron ParkerShot 26 was a good shot, no LH dropouts.
Jul 20 2006 04:50:44:600PM1060720028Ron ParkerGood shot, RF went through. Next: Raise power again, slide plasma 4 mm away from grill during pulse. (Decreased RCUR by 2mm at end of pulse.)
Jul 26 2006 01:21:46:193PM1060720029Ron ParkerShot 29 went well, full LH pulse ~750 kW. Good shot.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:05:03:223AMPlasmaOk
209:20:05:463AMPlasmaOk
309:34:30:640AMPlasmaOk
409:50:59:460AMPlasmaOk
510:24:02:253AMPlasmaOk
610:36:34:650AMPlasmaOk
710:51:26:750AMPlasmaOk
811:10:22:490AMPlasmaOk
911:27:06:217AMPlasmaOk
1011:42:50:143AMPlasmaOk
1112:14:06:797PMPlasmaOk
1212:30:36:163PMPlasmaOk
1312:44:39:463PMPlasmaOk
1412:57:09:940PMPlasmaOk
1501:12:41:930PMPlasmaOk
1601:25:31:637PMPlasmaOk
1701:40:14:673PMPlasmaBadOH2L Comm Flt
1802:03:03:823PMPlasmaOk
1902:32:50:977PMPlasmaOk
2002:52:35:967PMPlasmaOk
2103:06:46:690PMPlasmaOk
2203:19:58:383PMPlasmaOk
2303:32:31:763PMPlasmaOk
2403:45:06:067PMPlasmaOk
2503:59:39:350PMPlasmaOk
2604:12:35:250PMPlasmaOk
2704:30:12:003PMPlasmaOk
2804:43:58:947PMPlasmaOk
2904:58:11:007PMPlasmaOk