Alcator C-Mod Run 1031024 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader: Unknown (shots 1-30)

Operators
Session leader(s): Unknown
Physics operator(s):Ron Parker
Engineering operator(s):Bill Cochran

Engineering Operator Run Comment
Plasma Startup And Conditioning

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:37:19:600PM
Author: Ron Parker



Purpose: Plasma startup and conditioning

Physics operator: Parker
Engineering operator: Cochran


ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00.
Bake at 60 C overnight as well.

Run begins at 9:00 and ends at 17:00.

Power systems the same as on 1031023015 including control coil settings.

Gas setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC)
fill C-side with 30 psi D2 Hybrid enabled (PG3)

Ninja should be setup with Neon gas fill @ 400 Torr

Enable the following gate valves: ECE, VUV, DNB

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RF Setup: Transmitters 1,2,3, and 4 in RUN ON by 8:00 am

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Run Plan: Continue running cleanup plasmas while monitoring H/D, etc.

RF Group will continue antenna conditioning.
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The run started slowly, first because of finishing repairs to the chopper
power supply, which had failed during the previous run, and second due to
misfiring in the control of an EF bank.charging circuit. The first 6 shots
were devoted to troubleshooting and correcting these problems.Thus the first
plasma shot was shot 7, and this occurred at about 11:30, somewhat later
than had been anticipated.

Shot 7 ran well and essentially reproduced shot 1031023015, from which it was
loaded. The RF ran sporadically, as it did all day, and the plasma responded
with sporadic H-modes.

Shot 8 was a dud, shot 9 ran well, similar to shot 7, but shot 10 was again
a dud. The machine seemed to be in an "every-other-shot" mode.

After fine tuning the EF4 current, the machine started up reliably but
disrupted regularly at ~ 0.6 sec for the next 5 shots. Finally it was
discovered that the Ninja valve was injecting Neon, as called for in the run
plan, instead of Helium as the operator had thought. Turning off the Ninja
valve cured the disruption scenario. After this was discovered, the Neon
fill was reduced to 2 psi from 8, and disruptions were not a problem for
the remainder of the run.

Shots 17-20 went off well at 800 kA, and these were used to investigate
Neon emission from CXRS with the NBI. No definitive signal of Neon X was
observed. For shot 21, and earlier 900 kA shot was loaded, but the shot was
a dud.Shot 22 did run at 900 kA, but shot 23 was again a dud. At this point
shot 19 was reloaded since startup seemed reliable for this shot's settings.

Shots 24, 25 and 26 all ran well at 800 kA (RF still sporadic), but 27 was a
dud.28 went off well, but 29 was a dud. Finally, shot 30 went off as
programmed.

Scorecard:6 shots, no plasma due to engineering problems; 6 duds; 5 disruptions
due to Neon injection; and 13 full shots useful for RF conditioning.



Session Leader Comments

Physics Operator Comments
Oct 24 2003 10:14:55:513AM1031024001Ron ParkerShot 1 was a chopper power supply test. The chopper fault that occurred yesterday has been
repaired.
Oct 24 2003 10:16:10:463AM1031024002Ron ParkerShot 2 was also a also a chopper power supply test, at higher current.
Oct 24 2003 10:21:03:680AM1031024003Ron ParkerShot 3 was set up to be a plasma shot, but there was a problem with the charging supply for
EF1U coil. The shot was aborted prior to commutation.
Oct 24 2003 10:48:18:533AM1031024004Ron ParkerShot 4 was a test of the Ef charging circuit.

Next shot will be another test.
Oct 24 2003 10:54:36:920AM1031024005Ron ParkerThe charging power supply did not go again. There will be another test shot
Oct 24 2003 11:23:05:883AM1031024006Ron ParkerShot 6 again tested the charging circuit. The problem is in the control circuit, not the power circuit itself.
The problem has at least temporarily been fixed by Joe and Yuri. We'll go ahead
with plasma on the next shot.
Oct 24 2003 11:36:53:073AM1031024007Ron ParkerFinally, a plasma shot. Patience is a virtue.

Shot ran pretty much as shot 15 from yesterday, which was loaded.
RF was sporadic as were the H-modes
Oct 24 2003 11:47:50:880AM1031024008Ron ParkerShot 8 was a dud.

Power room and cell entries, then try again.
Oct 24 2003 12:04:49:507PM1031024009Ron ParkerAfter delicately fine-tuning absolutely nothing, the shot went. Plasma is similar to
shot 7. A few H-Modes, peak n_e.L(4) ~ 1.5.
Oct 24 2003 12:22:53:790PM1031024010Ron ParkerShot 10 was a dud. Very strange since shot 9 started up well. We seem to be in an every-other-shot
mode. No changes, try again.
Oct 24 2003 01:05:21:507PM1031024011Ron ParkerShot 11 started up well, but disrupted at 0.65 sec.
We've added 10 A to EF
Oct 24 2003 12:48:25:067PM1031024012Ron ParkerShot 13 started OK, but again disrupted at 0.65 sec.

I will lower the current slightly for next shot.
Oct 24 2003 01:07:56:473PM1031024013Ron ParkerShot 13 again disrupted --3 in a row at same time. Next shot: no Argon
Oct 24 2003 01:19:10:357PM1031024014Ron ParkerAgain, a disruption at 0.64 sec. Next shot: Move X-point down 1 cm and
to the inside 1 cm..
Oct 24 2003 01:45:57:477PM1031024015Ron ParkerShot 15 disrupted again, thus the divertor strike point is not the issue.

Ooooops! Ninja was activated as if it had been backfilled with He. However, the run
plan called for it to be backfilled with Ne. Massive amounts of Neon disrupt
tokamaks. Daah.

Next shot: No Ninja
Oct 24 2003 01:48:29:473PM1031024016Ron ParkerMystery solved. No Ninja, no disruption. Apologies to all who had been falsely accused of
causing the disruption.

On the next shot, Neon will be injected at 2 psi, down from 8. Argon back on.
Oct 24 2003 02:44:48:960PM1031024017Ron ParkerShot 17 went as programmed, no disruption with Ninja, but also no Ne signal
from beam.
Oct 24 2003 02:45:55:333PM1031024018Ron ParkerShot 18 went off as programmed. Ninja operated, but no Ne signal.
Oct 24 2003 02:46:46:867PM1031024019Ron ParkerShot 19 went off as programmed, still no sign of Neon from beam spectroscopy.
Oct 24 2003 02:48:34:147PM1031024020Ron ParkerShot 20 went off as programmed. Next shot: Reload shot 1031024009
Oct 24 2003 03:00:15:137PM1031024021Ron ParkerShot 21 was a dud. Shot 009 had an EF4 current of -1310, whereas subsequent shots had 1320.
EF4 will be increased to -1320.
Oct 24 2003 03:21:49:183PM1031024022Ron ParkerShot 22 ran well, current increased to 900 kA. After tis shot, vacuum gate valve will close at end of
shot and stay closed for 8 minutes, for wall retention studies.
Oct 24 2003 03:36:19:000PM1031024023Ron ParkerShot 23 was a dud. Reload shot 19. Result of keeping main vacuum valve closed?
Oct 24 2003 03:40:50:247PM1031024024Ron ParkerShot 24 came back, similar to earlier 800 kA shots, e.g, shot 19.
Oct 24 2003 03:59:55:640PM1031024025Ron ParkerShot 25 went of OK. No changes comng up.
Oct 24 2003 04:19:48:560PM1031024026Ron ParkerShot 26 ran well. No Changes.
Oct 24 2003 04:23:23:323PM1031024027Ron ParkerShot 27 was a dud. Next shot: no changes.
Oct 24 2003 04:57:56:757PM1031024028Ron ParkerShot 28 went off as programmed. RF still conditioning.
Oct 24 2003 04:57:20:100PM1031024029Ron ParkerSo far, no clear sign of Neon X line from CXRS.
Shot 29 was a dud. Next shot will likely go. Gate valve still closing after shots.
Oct 24 2003 05:04:15:977PM1031024030Ron ParkerShot 30 ran well, as expected.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:42:16:130AMTestOk
209:53:47:497AMTestOk
310:08:43:893AMPlasmaBadEF1U Comm.SW Charging supply error
410:36:10:730AMTestBadEF1U cap. bank charge test
510:47:54:830AMTestBadEF1U carge test
611:15:10:420AMTestOk
711:26:45:160AMPlasmaOk
811:41:58:273AMPlasmaOk
911:56:02:480AMPlasmaOk
1012:11:42:220PMPlasmaOk
1112:25:16:333PMPlasmaOk
1212:39:09:980PMPlasmaOk
1312:53:17:720PMPlasmaOk
1401:08:18:940PMPlasmaOk
1501:21:41:603PMPlasmaOk
1601:35:36:687PMPlasmaOk
1701:52:35:487PMPlasmaOk
1802:06:21:583PMPlasmaOk
1902:24:04:260PMPlasmaOk
2002:40:11:670PMPlasmaOk
2102:54:23:017PMPlasmaOk
2203:07:44:350PMPlasmaOk
2303:23:15:057PMPlasmaOk
2403:36:32:797PMPlasmaOk
2503:50:23:707PMPlasmaOk
2604:05:11:227PMPlasmaOk
2704:18:54:967PMPlasmaOk
2804:32:11:643PMPlasmaOk
2904:46:34:507PMPlasmaOk
3005:00:46:147PMPlasmaOk