Alcator C-Mod Run 1050822 Information

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Miniproposals
Miniproposal:430
Date Filed: 7/26/2005
Title:Localization of the effect of boronization
First Author:Bruce Lipschultz
Session Leader:Earl Marmar (shots 1-14)
Miniproposal:433
Date Filed: 7/29/2005
Title:Fueling in H-modes as a function of pedestal density
First Author:Jerry Hughes
Session Leader:Jerry Hughes (shots 15-22)

Operators
Session leader(s):Earl Marmar,Jerry Hughes
Physics operator(s):Ron Parker,Jim Irby,Ron Parker
Engineering operator(s):Gary Dekow,Sam Pierson,Bill Parkin

Engineering Operator Run Comment
MP430 Localization of Effects of Boronization; SL: Marmar; PO: Parker; E

Session Leader Plans
Entered: Aug 22 2005 09:44:34:713AM
Author: Earl Marmar
Session leader plan for 1050822

MP430 Localization of Effects of Boronization

Over the weekend: ECDC in D2 (P = 2e-4 gauge), bake at 60 C

On Monday morning, prior to the start of the run:

Boronize for 1 hour
ECDC scan from 44 to 103 cm, dwell at 70 cm
100% duty factor on magnetron (no flashing)
Standard pressures, using 20% B2D6 / 80% He bottle (from GA)

followed by 1 hour ECDC in Helium, ending by 8:30
[Note: because of a magenetron problem, we decided not to do the post-boronization He ECDC]

Be set up for between-shot boronization during the run

ICRF: E and J-4 will be needed

Shot plan:

Start from a shot like 1050818025 (1 MA, LSN, 1 cm outer gap)

1) Take ~3 shots to evaluate where we are with the 1 hour boronization and get the RF set. If we are still having problems with injections perhaps we should try changing the outer gap. [45 minutes]
2) 2 boronizations - 25 cm 20 minute scans (80-105, 62-87), pause at center [1.5-2 hours]
3) 10 cm, 10 minute scans working in from centers at 90 (90, 85, 80, 75, 70, 65, 55) [3.5 hours if no fizzles]
4) adjust the boronization pressure down [time permitting]

All boronizations will be done with 100% magnetron duty factor.

Physics Operators Plans
Entered: Aug 20 2005 08:25:29:030AM
Author: Ron Parker
CORRECTED Engineering Setup and Run Plan for 1050822

MP 430 Localization of the Effects of Boronization (Cont'd)

Session Leader: E. Marmar
Physics Operator: R. Parker

Weekend bake at 60 C and ECDC in Deuterium, p=2e-4 Gauge

Boronization from 6:30 to 7:30 followed by 1 hour of He discharge cleaning beginning at 7:45 and ending at 8:45

Parameters for boronization: Scan 44/70/103 cm,
Normal pressures, using the GA diborane bottle (20% B2D6 / 80% He)
100% duty cycle on magnetron (not pulsed)

Setup for between shot boronization

Run Begins at 9:00 and ends at 5:00

Power Systems as on 1050818025

RF in run on by 6:15 (E and J-4 sources)

A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and enabled.

Gas Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar plus 1 psi neon Hybrid DISABLED (PG1)
leave B-side upper as is He3 Hybrid DISABLED (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)

Enable the following gate valves and shutters: ECE, VUV, Z-bolo shutters

Session Leader Summaries
Entered: Aug 22 2005 06:21:23:197PM
Author: Jerry Hughes
Shots 15--22: Made initial steps on MP433. Injections limited most discharge attempts, particularly when
RF power (or its ramp rate) was highest. Reducing the demands on the RF improved things, and shots 20 and
22 had long H-modes. NINJA puffs with 10psi and 20psi D2 were created on shots 21 and 22, producing in
both cases a slight rise in overall density (though not in the edge pedestal) and appearing to stabilize the
growth of radiated power somewhat. 10 minutes of boronization was applied before most shots; the beneficial
effects of this technique seemed to wear off about 200ms into most H-modes. Will proceed tomorrow, after a
somewhat longer evening boronization.
Entered: Aug 23 2005 04:09:03:837PM
Author: Earl Marmar
Summary for first part of 1050822
MP 430 Boronization localization

Session Leaders: E. Marmar/B. Lipschultz


We got off to a slightly slow start as the 1 hour pre-run boronization did not start until 8:20 am. Because of this, we decided to eliminate the post boronization He ECDC and go straight to plasmas.

The 1 hour boronization gave decent conditions. Shot 3 and 5 were the first 2 plasmas, and injections were causing some problems. Shot 5 had a fairly steady h-mode. Shot 6 disrupted early in h-mode.

By shot 9, which followed 2 early disruptions (prior to RF turnon), the boronization was largely worn off.

We accomplished part 2 of the plan: boronizations with 25 cm scans in overlapping regions (shots 10 and 12). The early h-mode in shot 12 (62/74/87) was slightly better than that in shot 10 (80/90/105); shot 10 also disrupted before 1 second.

Next we did 2 of the planned 10 minutes scans: (75/80/85) before shot 14 and (65/70/75) before shot 15/16. Shot 14 was steadier than 16, with the latter getting slowed by an injection early in the first h-mode.

After shot 16, it was decided to switch to MP433 "Fueling in H-modes as a function of pedestal density" (J. Hughes, session leader). This MP will continue to use between-shot boronization.

shot scan (min/dwell/max) Scan time H89 (peak)
3 44/70/103 60 1.39
5 none 1.74
6 none 1.34
9 none 1.27
10 80/90/105 20 1.67
11 none 1.39
12 62/74/87 20 1.79
13 none 1.43
14 75/80/85 10 1.59
16 65/70/75 10 1.63

Physics Operator Summaries
Entered: Aug 22 2005 05:45:14:023PM
Author: Ron Parker
The run started late due to failure of the ECDC magnetron. This also voided the ECDC that had been planned after boronization.

The initial shots were a dud, a fizzle and an early disruption. This was followed by a dud due to a failure of the pulse gas PLC. Fianlly, shot 5 resulted in a full length plasma, reaching 175 kJ and peak neutron rate of 6e13. The next few shots disrupted early, and then things began to settle down at shot 11; nevertheless there were two fizzles and one disruption in the sequence that ended with shot 22.

These shots featured between shot boronization, usually for 10 minutes; typically, the first shot after boronization had decent stored energy and neutron emission, the next had lower performance, indicating that the improvement due to between shot boronization is temporary, lasting for less than the full RF duration in one shot. (pulse gas prefill was 8 ms duration for the first shot after boronization, and 18 ms for the next shot.)

Scorecard: 22 shots, 11 full length, 6 disruptions, 2 duds and 3 fizzles.

Session Leader Comments
Aug 22 2005 09:55:28:633AM1050822001Earl Marmarprior to this shot,
1 hour ECDC boronization
scan 44/70/103
20%B2D6/80%He
100% duty factor (no flashing)

Because of problem with the magnetron, got a slightly late start, and we decided to forego the post boronization ECDC in He

Went into init at P=3.8e-6 gauge

dud
Aug 22 2005 09:55:06:667AM1050822002Earl Marmartry again

fizzle



Aug 22 2005 10:29:10:510AM1050822003Earl Marmarplasma

H-mode, 145 kJ, H89 ~ 1.4 and steady Prf = 2.8 MW
until 0.88 sec, big increase in Prad, followed by disruption
Aug 22 2005 10:50:49:400AM1050822005Earl Marmarplasma

good shot
lumpy current rise
a few RF trips early in H-mode, then settles to fairly steady
H89 ~ 1.6 to 1.7, Prf ~ 2.8 MW, Wtot ~ 170 kJ
total neutrons (.7 < t <1.5) = 1.99e13
Aug 22 2005 10:52:03:680AM1050822006Earl Marmarplasma

h-mode, Prad high from 0.85 s, then disrupt
Aug 22 2005 11:06:07:230AM1050822007Earl Marmarmove strike point higher on the outer divertor

early disruption (before the rf)


Aug 22 2005 11:54:39:493AM1050822009Earl Marmarplasma

multiple h-modes
some RF trips
H89 ~ 1.3
total neuts = 8.4e12 (.7 < t < 1.5)
Aug 22 2005 12:51:05:917PM1050822010Earl MarmarPlan 2(a) from the run plan

prior to this shot, ECDC boronize 20 minutes
scan 80/90/105
100% duty factor

go to init at P~4e-6 gauge

plasma
H-mode, heading up, H89 ~ 1.67, then Prad increase and disruption
Aug 22 2005 12:48:41:120PM1050822011Earl Marmarno additional boronization prior to this shot

slow the RF power ramp-up

plasma

2 H-modes, first ended by injection
H89 ~ 1.4


Aug 22 2005 01:30:56:557PM1050822012Earl Marmar2(b) from the run plan
prior to this shot, ECDC boronize 20 minutes
scan 62/74/87
100% duty factor

go to init at P~4e-6 gauge

plasma
H-mode
H89 ~ 1.8, falling slowly until 1.4 seconds, then Prad increases above 1 MW (2*prad_2pi)
total neutrons = 1.65e13 (.7
Aug 22 2005 01:29:03:417PM1050822013Earl Marmarno additional boronization prior to this shot

plasma

steady H-mode
Prad is higher
H89 ~ 1.4 early, then falling

total neutrons = 7.4e12
Aug 22 2005 01:55:45:040PM1050822014Earl Marmarprior to this shot
ECDC boronization for 10 minutes
75/80/85
100% duty factor

plasma
steady h-mode
h89 ~ 1.6 and then slowly dropping
total neutrons = 1.33e13
Aug 22 2005 02:46:55:980PM1050822015Earl Marmarprior to this shot, ECDC boronize for 10 minutes
scan 65/70/75
100% duty factor

fizzle
Aug 22 2005 02:59:48:980PM1050822015Jerry HughesAttempt to repeat shot 14 with longer RF flattop.
No plasma.
Next shot: Retry.
-
Aug 22 2005 02:57:43:180PM1050822016Earl Marmarno additional boronization following shot 15 fizzle

plasma

first h-mode h89 ~ 1.6, then injection
second h-mode h89 ~ 1.15

total neutrons = 7.9e12
Aug 22 2005 02:59:05:307PM1050822016Jerry HughesDischarge was satisfactory, but a big injection kills the H-mode at 0.96s.
2nd H-mode is a good target for puff. Need to try for a steady H-mode of ~0.5s length.
Next shot: Retry shot. Lower slope of RF ramp, based on the premise that this reduces the
likelihood of injections.
Aug 22 2005 03:21:46:930PM1050822017Jerry HughesInjection, followed by disruption, with RF at full power.
Next shot: Lower total RF to 2.3MW
Aug 22 2005 03:26:37:133PM1050822018Jerry HughesPrad fraction is high, multiple H-modes. YAGs failed.
Next shot: Boronize and repeat shot.
Aug 22 2005 04:35:48:337PM1050822020Jerry Hugheslong H-mode, as desired. Prad hits steady state at about 1.25s, then H-mode deteriorates.
May have to be satisfied with this.
Next shot: Repeat, with NINJA puff, 10psi, 1.2--1.5s
Aug 22 2005 04:56:48:490PM1050822021Jerry HughesInjection hits just before NINJA puff. Some rise on TCI, core n_e.
Next shot: Repeat, with NINJA puff, 20psi, 1.2--1.5s
Aug 22 2005 05:36:39:570PM1050822022Jerry HughesShot goes well. Confinement in H-mode begins to degrade prior to NINJA puff at 1.2s.
Density increase on TCI, central n_e. Edge Te, Prad appear suppressed by puff.
End of run. Will continue tomorrow after a small overnight boronization.

Physics Operator Comments
Aug 22 2005 05:48:12:883PMRon ParkerShot 22 ran well, but similar sagging of both stored energy and neutron emission.
Aug 22 2005 08:54:39:730AM1050822001Ron ParkerThe magnetron used for ECDC failed this morning and had to be replaced by the spare. This has caused a delay, estimated to be 2 hours if no change in the setup.

Instead, we'll forego the ECDC in He. Boronization began at 8:20. Assuming 1 hour
of boronization, the first shot should be run at ~ 9:30.
Aug 22 2005 09:51:19:680AM1050822001Ron ParkerFirst shot was a dud. Possible problems: fill pressure too low (~2.7e-4) and/or
Bz too negative (-.001 @ 5 ms). Next: Double fill gas (from 8 to 16 ms) and
increase IC_EF4U from -1310 to -1290.
Aug 22 2005 09:57:34:730AM1050822002Ron ParkerShot 2 was a fizzle -- current rise a bit fast.
Next: Increase fill pulse to 21 ms to slow current rise,
reduce IC_EF4U by 10 A to -1300 (Bz was slightly too positive.)
Aug 22 2005 10:15:49:307AM1050822003Ron ParkerShot 3 started up reasonably well, but disrupted at 0.9 s.
Meanwhile, a power room entry alarm went off shortly after shot indicating
entry from RF lab. However, door was securely locked and entry was not possible. The conclusion is that this was a false indication.

Next: no change, try again.




Aug 22 2005 10:26:02:323AM1050822004Ron ParkerShot 4 was a dud -- no gas. Gas was setup properly so the PLC must have
failed to operate. Try again with same setup.
Aug 22 2005 10:43:51:587AM1050822005Ron ParkerShot 5 was a full shot, although the current rise was ugly. Nevertheless,
stored energy reached 175 kJ and neutron rate reached 6e13/s.

Suggestion is to delay density rise by ~100 ms for shot 6.
Aug 22 2005 10:50:27:180AM1050822006Ron ParkerCurrent rise was improved on this shot, but it disrupted at ~ 1s

We'll move the strike point up for next shot by increasing ZXL by 1 cm.
Aug 22 2005 11:02:07:557AM1050822007Ron ParkerShot 7 disrupted early.

Jim Irby taking over as PO.
Aug 22 2005 11:32:23:010AM1050822008Jim IrbyZXL to -.01 m at 0.55 s then ramp to 0.0 m at 0.75 s

early disruption
Aug 22 2005 11:31:52:337AM1050822009Jim Irbyreloaded shot 1050822006
increased early Ip rise to 750kA at 0.2 s

plasma into rampdown --- Prad up and neuts down from shot 005

will boronize for 20 minutes before next shot
Aug 22 2005 12:15:40:603PM1050822010Jim Irbyprefill from 21 to 8 ms

plasma for 0.95 s until injection killed us


Aug 22 2005 12:39:20:057PM1050822011Jim Irbyprefill to 18 ms from 8 ms

plasma into rampdown
Aug 22 2005 12:46:19:917PM1050822011Ron ParkerShot ran well with full ramp down.

Next: Boronize for 20 minutes before next shot. 8 ms prepuff.
Aug 22 2005 01:13:22:823PM1050822012Ron ParkerShot 12 ran well, 175 kJ, 6e13 neutrons, But radiated power still comes up at ~ 1.2 sec. Next: Repeat, increase gas to 18 ms.
Aug 22 2005 01:35:43:447PM1050822013Ron ParkerShot 13 ran well, with degradation in stored energy and neutrons relative to shot 12. Next: Boronize for 10 minutes, repeat shot. Prefill set at 8 ms.
Aug 22 2005 02:00:10:510PM1050822014Ron ParkerShot 14 ran well, full length. Neutrons reached 4e13, W ~ 160 kJ.

Next: Boronize for 10 minutes, 65, 70, 75.
Jerry Hughes becomes SL -- MP433. Same shot.
Aug 22 2005 02:23:07:667PM1050822015Ron ParkerShot 15 fizzled. Try again. Increase prefill to 18 ms.
Aug 22 2005 02:59:06:963PM1050822016Ron ParkerShot 16 ran, poor quality H_mode -- W ~ 110-120 kJ, neutrons ~ 1e13 in second H mode. Next: 10 minute boronization, same settings as last one (65/70/75).
Aug 22 2005 03:07:55:430PM1050822017Ron ParkerShot 17 ran, but disrupted at 1.1 sec. Repeat with slightly less RF (2.3 vs. 2.8)
Aug 22 2005 03:25:58:713PM1050822018Ron ParkerShot ran full length, but H-mode is poor quality.
Next: Boronize, 10 minutes, retry.
Aug 22 2005 03:51:27:870PM1050822019Ron ParkerShot 19 fizzled. Repeat, gas back to 18 ms prefill.
Aug 22 2005 04:09:02:430PM1050822020Ron ParkerShot 20 went off, some injections, sagging W and neutrons.

Next: Boronize, then puff gas into shot.
Aug 22 2005 04:54:48:223PM1050822021Ron ParkerShot 21 ran full length, and gas from Ninja was injected.

Next: Boronize again, and increase the Ninja puff. This will be the last shot.

Aug 22 2005 05:48:32:307PM1050822022Ron ParkerShot 22 ran well, but similar sagging of both stored energy and neutron emission.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:36:30:103AMPlasmaOk
209:49:11:743AMPlasmaOk
310:02:49:917AMPlasmaOk
410:17:11:650AMPlasmaOk
510:30:15:540AMPlasmaOk
610:42:42:197AMPlasmaOk
710:55:02:133AMPlasmaOk
811:10:05:650AMPlasmaOk
911:24:26:010AMPlasmaOk
1012:09:36:370PMPlasmaOk
1112:21:55:680PMPlasmaOk
1201:02:42:383PMPlasmaOk
1301:15:34:790PMPlasmaOk
1401:45:32:680PMPlasmaOk
1502:17:23:447PMPlasmaOk
1602:30:00:167PMPlasmaOk
1703:02:15:680PMPlasmaOk
1803:15:03:150PMPlasmaOk
1903:45:51:947PMPlasmaOk
2003:58:24:133PMPlasmaOk
2104:34:44:900PMPlasmaOk
2205:06:30:150PMPlasmaOk