Alcator C-Mod Run 1060727 Information

Back to runs

Miniproposals
Miniproposal:455
Date Filed: 5/26/2006
Title:Determination of LHCD efficiency
First Author:J. Randall Wilson
Session Leader:J. Randall Wilson (shots 1-21)

Operators
Session leader(s):J. Randall Wilson
Physics operator(s):Ron Parker
Engineering operator(s):Sam Pierson,Gary Dekow,Bill Parkin

Engineering Operator Run Comment
MP #418 LH System conditioning

Session Leader Plans
Entered: Jul 27 2006 09:23:50:653AM
Author: J. Randall Wilson
Finish LHCD campaign for FY 2006 run

1. Complete phase scan at 120 degrees. Had difficulty last run due to high intrinsic reflection

2. Push power toward 1 MW. Launcher has continued to improve with each run

3. Attempt to obtain full CD At 1 MW this should be ~ 400 kA

4. Explore ICRF plus LH

Physics Operators Plans
Entered: Jul 27 2006 05:15:31:987PM
Author: Ron Parker
Physop Plan and Engineering Setup Thursday, July 27, 2006

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

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

Power systems as on 1060720
A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and enabled.
C-coil Start=0.3sec, Invert=2.0sec

ICRF will be required for the last third of the run. All transmitters should be ready.

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.

Objectives: Obtain X-Ray data for 120 deg phasing for comparison with 60 and 90.

Increase power to 1 MW and obtain full CD

Explore ICRF interactions and conpatibility with LH.

See also SL plan.

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 27 2006 05:11:45:920PM
Author: Ron Parker
The run was punctuated by system problems. First an intermittent in the TMX/Chopper power supply, causing the loss of 2 shots due to early disruption; second the dropping out of the digitizer for CPS Cart 3 (in the process of fixing which the whole CPS digitizer went down); and third, the loss of a TF breaker which resulted in an early termination of the run.

Nevertheless, 20 shots were fired off, and 120 deg phase progression data were recorded for comparison to 60 and 90 deg data obtained from run 1060720. Attempt to raise the power only barely exceeded the record of 750 kW from run 1060720, and was made difficult by frequent trips.

The good news is that the lost time will be made up on 1060728, which was previously scheduled as the day to begin the warmup for cryopump installation.

Scorecard: 20 plasma attempts, no duds or fizzles and 2 disruptions due to intermittent in TMZ/Chopper supply.

Session Leader Comments
Jul 27 2006 09:24:25:217AM1060727001J. Randall Wilsonfirst shot disrupted at ~0.3 s
Jul 27 2006 09:51:04:963AM1060727002J. Randall Wilsonmultiple arcs 13b intrinsic reflection justy like last week
Jul 27 2006 10:18:18:537AM1060727004J. Randall Wilsonhigher power only two good sections

go to power ramp next
Jul 27 2006 10:26:27:443AM1060727005J. Randall Wilsonramp 60-80 kW per klystron then flat

one dropout ~0.2 V drop
Jul 27 2006 10:48:11:530AM1060727006J. Randall Wilsonramp 60-90 kW per klystron then flat

long dropout in flat-top

0.3 V drop
Jul 27 2006 10:56:48:143AM1060727007J. Randall Wilsonramp 60-100 kW per klystron then flat

no drop-outs but density higher

smaller ECE signal
Jul 27 2006 11:20:02:060AM1060727008J. Randall Wilsonramp 60-100 kW per klystron then flat

density back to normal

0.35 V drop

now go over to 60 degree phasing starting shot 009
Jul 27 2006 11:46:19:023AM1060727009J. Randall Wilsonchopper problem plasma stops early
Jul 27 2006 01:05:21:280PM1060727012J. Randall Wilsonfinally try again

couple of drops

central density > 1e20
Jul 27 2006 01:20:02:647PM1060727013J. Randall Wilsonbetter pulse lower density
Jul 27 2006 01:37:28:277PM1060727014J. Randall Wilson60-110 kW ramp

tripping on 23b due to intrinsic refection
Jul 27 2006 01:59:32:473PM1060727015J. Randall Wilson60-120 kW ramp

tripping on 23b due to intrinsic refection
Jul 27 2006 02:38:17:537PM1060727016J. Randall Wilson60-120 kW ramp

removed 23 from trip detection
Jul 27 2006 02:38:28:643PM1060727017J. Randall Wilson60-130 kW ramp

removed 23 from trip detection
Jul 27 2006 02:38:46:910PM1060727018J. Randall Wilson60-140 kW ramp

removed 23 from trip detection

injection and arcing
Jul 27 2006 02:54:50:057PM1060727019J. Randall Wilson60-140 kW ramp

removed 23 from trip detection

ramp good then multiple arcs not obvious why
Jul 27 2006 03:09:59:360PM1060727020J. Randall Wilson60-140 kW ramp

removed 23 from trip detection

better sawteeth finally stable

Physics Operator Comments
Jul 27 2006 09:14:30:057AM1060727001Ron ParkerTCI needed alignment -- 15 minute delay. First shot coming up.
Jul 27 2006 09:24:50:220AM1060727001Ron ParkerFirst shot disrupted at 0.3 s.

Jul 27 2006 05:14:11:000PM1060727001Ron ParkerToday's run will be devoted to lower hybrid with 3 goals:

i) Get X-ray data at 120 deg phasing;
ii)Bring power up toward 1 MW;
ii)Try to combine LH with ICRF.

All systems are functional at 8:50 AM and we do not expect delay in starting up.
Jul 27 2006 09:49:48:227AM1060727002Ron ParkerShot 2 went Off OK, LH tripped 12 times, no pulse. Channel 13 seems to be the culprit. For next shot, reduce outer gap by 4 mm to bring up coupler density.
Jul 27 2006 11:14:04:510AM1060727003Ron ParkerShot 3 was OK, RF had long period without trips, but 3 dropouts near beginning and end.
Jul 27 2006 11:15:23:980AM1060727004Ron ParkerShot 4 went off OK, two RF pulses, too many dropouts.
Jul 27 2006 11:17:19:120AM1060727005Ron ParkerShot 5 was good, started RF ramping. Good period of uninterrupted RF.
Jul 27 2006 11:18:43:543AM1060727006Ron ParkerShot 6 was OK, RF ramped but several trips near beginning of flattop.
Jul 27 2006 11:21:28:577AM1060727007Ron ParkerShot 7 was OK, but density was higher than reference shot. Repeat.

No RF trips.
Jul 27 2006 11:11:53:447AM1060727008Ron ParkerShot 008 went off OK, and the density was back down to levels typical of the shots before 007.

Good LH pulse, 120 deg phasing. Now we'll go the 2nd part of run, namely power pushing at 60 deg.
Jul 27 2006 11:23:47:937AM1060727008Ron ParkerShot 8 was an excellent shot, density returned to reference level and no RF trips.

This is a good shot to compare with 60 and 90 deg phasing at 500 kW level.

Reflection ~ 30%.
Jul 27 2006 11:45:16:147AM1060727009Ron ParkerShot 9 disrupted early, 22 ms. Chopper voltage is low, same problem as in shot 1.
Jul 27 2006 11:56:16:840AM1060727010Ron ParkerShot 10 had same chopper problem. Disrupted at 0.27 s.
Jul 27 2006 12:47:48:510PM1060727010Ron ParkerNext shot will be to troubleshoot TMX/Chopper suppply problem.
Jul 27 2006 01:01:16:607PM1060727011Ron ParkerShot 11 cycled the chopper supply, looked normal.

Go for plasma on next shot.
Jul 27 2006 01:14:15:050PM1060727012Ron ParkerShot 12 went off OK. Central density from Thomson is higher than what would have been expected from TCI. Probable TCI fringe loss.
Jul 27 2006 01:20:41:740PM1060727013Ron ParkerShot 13 was OK, RF stayed on until 1.26 s. 600 kW RF, 20% reflection.
Jul 27 2006 01:38:33:263PM1060727014Ron ParkerShot 14 was OK, Rf tripped repeatedly beginning at 1.13 s.

Try again, more power.
Jul 27 2006 02:22:08:653PM1060727015Ron ParkerShot 15 was OK.
Jul 27 2006 02:22:39:153PM1060727016Ron ParkerShot 16 went well.
Jul 27 2006 02:28:29:720PM1060727017Ron ParkerShot 17 ran well, density creeping up. Try to lower n on the next shot.
Jul 27 2006 03:58:54:643PM1060727018Ron ParkerShot 18 OK, frequent RF trips
Jul 27 2006 03:54:19:830PM1060727019Ron ParkerShot 19 was OK, lost data from cart 3 digitizer. RF tripped just before 1 s and did not recover.
Jul 27 2006 03:58:31:237PM1060727020Ron ParkerShot 20 was probably the best shot today, low loop voltage, nor sawteeth. But no CPS data!

Delay while Josh tries to get CPS digitizers working.


Engineering Operator Comments
ShotTimeTypeStatusComment
109:17:09:293AMPlasmaOk
209:34:49:270AMPlasmaOk
309:49:09:103AMPlasmaOk
410:06:59:593AMPlasmaOk
510:20:06:333AMPlasmaOk
610:34:41:807AMPlasmaOk
710:49:16:283AMPlasmaOk
811:02:20:287AMPlasmaOk
911:39:55:643AMPlasmaOk
1011:52:52:900AMPlasmaBadChopper low voltage
1112:48:18:107PMTestOkEFC Chopper Supply
1212:58:53:810PMPlasmaOk
1301:13:26:690PMPlasmaOk
1401:26:16:930PMPlasmaOk
1501:38:59:077PMPlasmaOk
1602:01:16:113PMPlasmaOk
1702:15:07:057PMPlasmaOk
1802:31:02:313PMPlasmaOk
1902:43:49:943PMPlasmaOk
2002:56:50:167PMPlasmaOk
2104:21:03:967PMPlasmaOk