Alcator C-Mod Run 1050218 Information

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Miniproposals
Miniproposal:355
Date Filed:11/12/2003
Title:ICRF Testing & Conditioning
First Author:Steve Wukitch
Session Leader:Steve Wukitch (shots 1-27)

Operators
Session leader(s):Steve Wukitch
Physics operator(s):Joseph Snipes
Engineering operator(s):Bill Cochran,Bill Byford,Ed Fitzgerald

Engineering Operator Run Comment
MP#355

Session Leader Plans
Entered: Feb 18 2005 11:36:58:870AM
Author: Steve Wukitch
Plan:

We will continue the simple and dull plasma operation for antenna
conditioning . We want to obtain as many discharges as possible to
plasma condition D and E antennas. Start with vanilla LSN, 5.4 T,
Ip=0.8 MA, nl_04=0.6 target discharge (1050216007). Upper null
discharges can be run if parties are interested (1050216013 is a good
starting point). The aim is to get 1 MW from each for 0.5 sec then
combine and maximize injected power. Monitor density and impurity
evolution for trends with RF power.

Physics Operators Plans
Entered: Feb 17 2005 01:55:45:690PM
Author: Joseph Snipes
MP#355:
SL: Wukitch
PO: Snipes

Overnight ECDC in D2, bake at 60C

Engineering setup:
Power systems as on 1050215007

Gas setup:
-----------
> fill B-Top with 6 psi D2 Hybrid Enabled (PG4)
> fill B-side lower with 1 psi Ar Hybrid DISabled (PG1)
> fill B-side upper with 30 psi D2 Hybrid DISabled (PG2)
> fill (former) C-side with 30 psi D2 Hybrid Enabled (PG3)

Torvac Setup:
--------------
GV1 closed, Bypass to RGA open
Torus gate valves closed in Pulse for 5min after shot

Gate valves:
ECE (assuming no vac problems) and Z-bolo/shutter open

---------------------------------------------------------
Plan:

We will continue the simple and dull plasma operation for antenna conditioning . We want to obtain as many
discharges as possible to plasma condition D and E antennas. Start
with vanilla LSN, 5.4 T, Ip=0.8 MA, nl_04=0.6 target discharge
(1050216007). Upper null discharges can be run if parties are
interested (1050216013 is a good starting point). The aim is to get 1
MW from each for 0.5 sec then combine and maximize injected power.
Monitor density and impurity evolution for trends with RF power.
---------------------------------------------------------

Session Leader Summaries
Entered: Feb 18 2005 07:03:24:103PM
Author: Steve Wukitch
E antenna plasma conditioning has progressed well. To increase power
further, FMIT#2 tuning needs to be improved at high power. The plate
impedance is too high to allow operation into plasma above 1.2 MW.

Initial plasma conditioning was attempted on D antenna. During vacuum
conditioning, Dave Johnson was in the cell when we were testing and
clearly heard ticking. We will pumped for an hour and back fill with
SF6 at 10 psi the stub tuner-phase shifter section. After pumping and
back filling with SF6, the matched line appeared to have an arc
between the switch and DC1. We need to pump and purge this line
before continuing with antenna operation.

There may have been arcing activities on D antenna as seen from camera
wide 2 view on shot 018. The cause is unclear though.

Physics Operator Summaries
Entered: Feb 18 2005 07:03:55:590PM
Author: Joseph Snipes
Overall, it was a successful run. The machine ran rather well. There were 21 plasmas of which 20 were full
length. The density feedback was failing by the end of the day, but did not do anything disasterous. See the
session leader summary for the RF performance. It seems that D was arcing, but E worked reasonably well. Still,
the H concentration was rather high except for shot 1. The walls need further conditioning.

Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax
1 1.975 0.832 2 1.832 0.828
3 0.621 0.752 4 0.000 0.037
5 1.690 0.810 6 1.698 0.811
7 0.000 0.022 8 1.972 0.830
9 1.970 0.832 10 1.836 0.826
11 1.737 0.824 12 1.808 0.821
13 0.000 0.041 14 1.845 0.830
15 1.898 0.828 16 0.000 0.042
17 0.000 0.036 18 1.881 0.827
19 1.881 0.826 20 1.897 0.824
21 1.911 0.828 22 1.910 0.827
23 0.000 0.048 24 1.938 0.824
25 1.911 0.822 26 1.885 0.821
27 1.888 0.822
Finished summary for 1050218 Total of 27 shots.
27 shots. 21 plasmas. 5 fizzles. 1 duds.

Session Leader Comments
Feb 18 2005 12:13:23:323PM1050218001Steve Wukitch001 BT~5.4T, Ip~0.8 MA, nl06~0.6
E: 1.0 MW [0.6,1.5]sec
result: plasma
E: ran 1 fault

no D antenna until we can isolate a breakdown problem (in the lines
hopefully)
Feb 18 2005 12:57:39:370PM1050218002Steve Wukitch002 BT~5.4T, Ip~0.8 MA, nl06~0.8
E: 1.0 MW [0.6,1.5]sec
result: plasma
E: ran 1 fault
Feb 18 2005 01:21:16:073PM1050218003Steve Wukitch003 BT~5.4T, Ip~0.8 MA, nl06~0.8
E: 1.2 MW [0.6,1.5]sec
result: plasma - early disruption
Feb 18 2005 01:21:59:120PM1050218004Steve Wukitch004 BT~5.4T, Ip~0.8 MA, nl06~0.8
E: 1.2 MW [0.6,1.5]sec
result: NTP
Feb 18 2005 01:38:38:760PM1050218005Steve Wukitch005 BT~5.4T, Ip~0.8 MA, nl06~0.8
E: 1.2 MW [0.6,1.5]sec
result: plasma
E: ran 5 faults

FMIT#2 FPA is overdriven at high power. We need to improve the high
power match next week.
Feb 18 2005 02:46:39:900PM1050218006Steve Wukitch006 BT~5.4T, Ip~0.8 MA, nl06~0.6
E: 1.2 MW [0.6,1.5]sec
result: plasma
E: ran 5 faults
Feb 18 2005 02:48:04:040PM1050218007Steve Wukitch007 test
Feb 18 2005 02:48:41:557PM1050218008Steve Wukitch008 BT~5.4T, Ip~0.8 MA, nl06~0.
E: 1.0 MW [0.6,1.5]sec
result: plasma
E: ran 1 fault
Feb 18 2005 02:52:50:197PM1050218009Steve Wukitch009 BT~5.4T, Ip~0.8 MA, nl06~0.
E: 1.0 MW [0.6,1.5]sec
result: plasma
E: ran 1 fault

D antenna appears to have a breakdown in the matched section of line
now. We filled the tuner with SF6 and it appears to be working better
than the matched side now.
Feb 18 2005 03:22:50:370PM1050218010Steve Wukitch010 BT~5.4T, Ip~0.8 MA, nl06~0.
E: 1.0 MW [0.6,1.5]sec
result: plasma
E: ran 1 fault
Ran D into dummy load to test if the switch is failing.
Feb 18 2005 03:24:31:730PM1050218011Steve Wukitch011 BT~5.4T, Ip~0.8 MA, nl06~0.
D: .15 MW [0.6,1.5]sec
E: 1.0 MW [0.8,1.5]sec
result: plasma
D: max faults (but improved over previous)
E: ran 4 faults
Feb 18 2005 03:26:45:277PM1050218012Steve Wukitch012 BT~5.4T, Ip~0.8 MA, nl06~0.8
D: .15 MW [0.6,1.5]sec
E: 1.0 MW [0.8,1.5]sec
result: plasma
D: max faults (but improved)
E: ran 3 faults
Feb 18 2005 04:20:18:353PM1050218013Steve Wukitch013 BT~5.4T, Ip~0.8 MA, nl06~0.8
D: .15 MW [0.6,1.5]sec
E: 1.0 MW [0.8,1.5]sec
result: fizzle
Feb 18 2005 04:20:38:557PM1050218014Steve Wukitch014 BT~5.4T, Ip~0.8 MA, nl06~0.8
D: .15 MW [0.6,1.5]sec
E: 1.0 MW [0.8,1.5]sec
result: D: max faults (but improved)
E: ran 4 faults
Feb 18 2005 04:20:48:557PM1050218015Steve Wukitch015 BT~5.4T, Ip~0.8 MA, nl06~0.8
D: .15 MW [0.6,1.5]sec
E: 1.0 MW [0.9,1.5]sec
result: D: max faults (but improved)
E: ran 4 faults
Feb 18 2005 04:21:16:540PM1050218016Steve Wukitch016 BT~5.4T, Ip~0.8 MA, nl06~0.8
D: .15 MW [0.6,1.5]sec
E: 1.0 MW [0.9,1.5]sec
result: fizzle
Feb 18 2005 04:30:39:887PM1050218017Steve Wukitch017 BT~5.4T, Ip~0.8 MA, nl06~0.8
D: .15 MW [0.6,1.5]sec
E: 1.0 MW [0.9,1.5]sec
result: dud
Feb 18 2005 05:00:15:387PM1050218018Steve Wukitch018 BT~5.4T, Ip~0.8 MA, nl06~0.8
D: .15 MW [0.6,1.5]sec
E: 1.0 MW [0.9,1.5]sec
result: plasma
D: max faults (improved?)
E: ran 2 faults
Camera wide-2 view showed some arcing activities on the top left corner
(C-side) of the D antenna between t = 1-1.2 sec. The D port power was small in
this time period. The plasma was affected somewhat (seen on 2pi, and nl04).
Feb 18 2005 05:07:45:887PM1050218019Steve Wukitch019 BT~5.4T, Ip~0.8 MA, nl06~0.8
D: .15 MW [0.6,1.5]sec
E: 1.0 MW [0.9,1.5]sec
result: plasma
D: max faults (worse)
E: clean.
No more arcing seen on the camera. But D port is still sick.
I may decide whether to stop running D after a couple more shots.
Feb 18 2005 05:23:36:993PM1050218020Steve Wukitch020 BT~5.4T, Ip~0.8 MA, nl06~0.8
D: .15 MW [0.6,1.5]sec
E: 1.0 MW [0.9,1.5]sec
result: plasma
D: max faults (going nowhere
E: clean.

The faults in D are all DC0 arcing as reported by computer.
Next get fast data in the cell to check more carefully.
If it is the case, I should stop running D.
Feb 18 2005 05:38:13:743PM1050218021Steve Wukitch021 BT~5.4T, Ip~0.8 MA, nl06~0.8
D: .15 MW [0.6,1.5]sec
E: 1.0 MW [0.9,1.5]sec
result: plasma
D: max faults
E: clean
Fast data from cell.
At D port faults, there are clearly DC0 refl spikes. Smaller spikes
are also seen in some DC1 refl signals.

Next, return to slow data. Redude D port power demand to 0.13 and see
whether it can run longer.
Feb 18 2005 05:48:32:760PM1050218022Steve Wukitch022 BT~5.4T, Ip~0.8 MA, nl06~0.8
D: .13 MW [0.6,1.0]sec
E: 1.0 MW [0.9,1.5]sec
result: plasma
D: max faults (Not better)
E: 1 fault.

Since D port does not get any better, I will not run it any more today.
Feb 18 2005 06:19:38:430PM1050218023Steve Wukitch023 BT~5.4T, Ip~0.8 MA, nl06~0.8
D: .13 MW [0.6,1.0]sec
E: 1.0 MW [0.9,1.5]sec
result:
fizzle
Feb 18 2005 06:21:06:917PM1050218024Steve Wukitch024 BT~5.4T, Ip~0.8 MA, nl06~0.8
E: 1.0 MW [0.7,1.5]sec
result:
E clean.

Next, slightly increase E power.
Feb 18 2005 06:41:16:510PM1050218025Steve Wukitch025 BT~5.4T, Ip~0.8 MA, nl06~0.8
E: 1.1 MW [0.7,1.5]sec
result:
E: 2 faults.

Next: raise E power again.
Feb 18 2005 06:52:04:993PM1050218026Steve Wukitch026 BT~5.4T, Ip~0.8 MA, nl06~0.8
E: 1.2 MW [0.7,1.5]sec
result:
E: 3 faults.

FPA screen current rose too much at the end of the pulse. Clearly, the transmitter
needs more tuning for higher power.

Next: reduce power to 1.0 MW level.
Feb 18 2005 07:02:39:900PM1050218027Steve Wukitch027 BT~5.4T, Ip~0.8 MA, nl06~0.8
E: 1.0 MW [0.7,1.5]sec
result:
E: clean

Physics Operator Comments
Feb 18 2005 12:10:55:400PM1050218001Joseph SnipesShot 1: Copied shot 1050216007 and increased B-side lower Ar gas pressure to 2 psi at Rice's request. Good shot.
Feb 18 2005 12:47:27:603PM1050218002Joseph SnipesShot 2: Raised nl04 to 8 x 10^19 m^-2. Problems with the Sherman computer of Jim Terry's slowing down the
acquisition from Shot 1. Tom turned off all actions to Sherman to keep it out of the shot cycle. Cell access
for Wukith, then we are once again ready for the shot. Good shot.
Feb 18 2005 01:10:47:180PM1050218003Joseph SnipesShot 3: Repeat. Disrupted at 0.62 s. Density increases too much early. Perhaps, there are some impurities
coming into the plasma.
Feb 18 2005 01:18:54:557PM1050218004Joseph SnipesShot 4: Reduced nl04 to 5 x 10^19 m^-2 again to see if that helps. Turned off NINJA puff, which was on for
some reason, though it is not clear if it was puffing. Fizzle!
Feb 18 2005 01:42:15:010PM1050218005Joseph SnipesShot 5: Both Br and Bz changed a lot after that disruption. If these changes are real, I need to compensate.
So, I've dropped Br0 by 0.5 mT to -0.003 and I've lowered EF4 from -1340 A to -1380 A. Just barely got the
current rise, but it did go. Disrupted in rampdown at 1.69 s. Lots of runaways from early on. Huge offset
changes in flux loop F15. Granetz claims it should be OK for shot 6.
Feb 18 2005 01:59:48:590PM1050218006Joseph SnipesShot 6: Return Br0 to -0.0025 T and EF4 to -1340 A. Reduced prepuff by 1 ms to 15 ms duration. Startup looks
better, but F15 is still flaky and it disrupted in rampdown at the same time as on shot 5.
Feb 18 2005 02:19:23:167PM1050218007Joseph SnipesShot 7: OH1 test at 10 kA to check the flux loop F15. The flux loop looks fine now.
Feb 18 2005 02:27:39:840PM1050218008Joseph SnipesShot 8: Repeat shot 6. NINJA turned back on puffing D2 at 1.3 s. Good shot.
Feb 18 2005 02:44:33:540PM1050218009Joseph SnipesShot 9: Repeat. Good shot.
Feb 18 2005 02:58:09:463PM1050218010Joseph SnipesShot 10: Increased nl04 to 7 x 10^19 m^-2. Good shot.
Feb 18 2005 03:11:24:840PM1050218011Joseph SnipesShot 11: Increased nl04 to 8 x 10^19 m^-2 ramping up more slowly than on shots 2 adn 3. Good shot.
Feb 18 2005 03:25:05:090PM1050218012Joseph SnipesShot 12: Reduced CLEARIN by 0.005 m to 0.005 m and increased RCUR by 0.0025 m to 0.6605 m to decrease the
inner gap by 0.5 cm for Ken Marr. Decreased prepuff by 1 ms to 14 ms duration. Good shot.
Feb 18 2005 03:37:28:963PM1050218013Joseph SnipesShot 13: Needed to reduce RCUR rather than increase RCUR to keep a constant outer gap. So, I've now changed
RCUR from 0.6605 to 0.6555 m. Fizzle!
Feb 18 2005 03:50:43:620PM1050218014Joseph SnipesShot 14: Try again with no changes. Good shot.
Feb 18 2005 04:03:14:090PM1050218015Joseph SnipesShot 15: Earl suggests keeping CLEARIN at 0.005 m throughout the rampdown to avoid disruptions in the rampdown.
So, I've changed CLEARIN to maintain 0.005 m out to 1.9 s. Reduced prepuff by 1 ms to 13 ms duration. Good
shot.
Feb 18 2005 04:17:29:400PM1050218016Joseph SnipesShot 16: Reduced ZXL to 0 to attempt to avoid disruptions in rampdown. Reduced CLEARIN and RCUR by 4 mm to
decrease the inner gap and maintain the outer gap where it was throughout the shot. Fizzle!
Feb 18 2005 04:30:31:040PM1050218017Joseph SnipesShot 17: Increased EF4 current by 10 A to -1330 A. Increased prepuff by 1 ms to 14 ms duration. Dud!
Feb 18 2005 04:47:41:527PM1050218018Joseph SnipesShot 18: Decreased EF4 by 25 A to -1355 A. Good shot.
Feb 18 2005 05:09:40:120PM1050218019Joseph SnipesShot 19: Increased CLEARIN after 1.64 s to attempt to avoid the disruptions in rampdown. Reduced CLEARIN
during the flattop by 1 mm to reduce the inner gap to 1 cm. Increased RCUR by 1.5 mm to reduce the outer gap
a bit. Good shot.
Feb 18 2005 05:13:54:590PM1050218020Joseph SnipesShot 20: Increased RCUR in the rampdown to attempt to keep the plasma diverted and avoid rampdown disruptions.
Good shot.
Feb 18 2005 05:33:13:387PM1050218021Joseph SnipesShot 21: Repeat. Good shot.
Feb 18 2005 05:45:39:603PM1050218022Joseph SnipesShot 22: Repeat. Good shot.
Feb 18 2005 05:54:10:790PM1050218023Joseph SnipesShot 23: Repeat. Fizzle!
Feb 18 2005 06:18:51:760PM1050218024Joseph SnipesShot 24: Reduced prepuff by 2 ms to 13 ms duration. Good shot.
Feb 18 2005 06:33:37:307PM1050218025Joseph SnipesShot 25: Increased prepuff by 1 ms again to 13 ms duration to try to avoid the early runaways. Good shot.
Feb 18 2005 06:46:37:620PM1050218026Joseph SnipesShot 26: Repeat. Good shot.
Feb 18 2005 06:59:23:400PM1050218027Joseph SnipesShot 27: Repeat. Good shot.

Engineering Operator Comments
ShotTimeTypeStatusComment
112:09:23:620PMPlasmaOk
212:45:23:743PMPlasmaOk
301:04:09:040PMPlasmaOk
401:17:17:917PMPlasmaOk
501:34:12:150PMPlasmaOk
601:47:28:790PMPlasmaOk
702:16:44:400PMTestOkOH1 PLC 10kA Test shot for a flux loop test
802:25:59:667PMPlasmaOk
902:42:50:137PMPlasmaOk
1002:55:49:277PMPlasmaOk
1103:09:47:870PMPlasmaOk
1203:22:45:090PMPlasmaOk
1303:35:44:400PMPlasmaOk
1403:48:33:713PMPlasmaOk
1504:01:22:493PMPlasmaOk
1604:13:52:743PMPlasmaOk
1704:28:14:480PMPlasmaOk
1804:40:43:243PMPlasmaOk
1904:59:42:493PMPlasmaOk
2005:12:03:197PMPlasmaOk
2105:25:58:557PMPlasmaOk
2205:39:52:213PMPlasmaOk
2305:52:12:930PMPlasmaOk
2406:17:19:213PMPlasmaOk
2506:29:49:480PMPlasmaOk
2606:45:04:620PMPlasmaOk
2706:57:26:137PMPlasmaOk