Alcator C-Mod Run 990909 Information

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Miniproposals
Miniproposal:214
Date Filed: 1/5/1999
Title:D and E-port RF System Commissioning
First Author:Steve Wukitch
Session Leader:Gerd Schilling (shots 1-19)
Session Leader:Steve Wukitch (shots 1-19)

Operators
Session leader(s):Gerd Schilling,Steve Wukitch
Physics operator(s):Dmitri Mossessian
Engineering operator(s):Frank Silva

Engineering Operator Run Comment
RF Conditioning/Mossessian, Silva

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:37:09:240PM
Author: To Be Determined
Physics operator summary for run 990909:

Run Plan and Engineering Setup:

SL: Wukitch/Schilling
PO: Mossessian

This run was a continuation of that scheduled for September 8, 1999.
The general purpose was to condition the RF antennas.

The run was scheduled to start at 10:00 and end at 17:00

_________________________
Engineering setup:

Two hours ECDC in D2 prior to run, finishing at least 1 hour before run.

Setup power supplies from 990908004

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid DISABLED
fill B-side upper with 6 psi of H2 Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid enabled
J-bottom pumped out Hybrid DISABLED
_______________________________________

Summary:

The run was delayed until 11:20 for RF work. First ten shots went well, although shots
1 and 2 used PCS setup loaded from shot 990908020 rather than 990908006 (I forgot to load
PCS) and some shots had slight hesitation in current rise. The prepuff length was reduced
first to 18 msec and then to 16 msec to help current rise. The lower x-point location was
reprogrammed after shot 4 to avoid the x-point drift towards divertor inner nose.
Shot 11 was a fizzle for no apparent reason. Shot 12 went OK without any PCS changes.
Shot 13 disrupted right after going into H-mode due to a large (probably RF-caused) injection.
Then followed a series of fizzles (4 shots) and shot 18 was a plasma again after multiple
Bz - Br tweeks and after changing RCUR offset to push the plasma out after breakdown.
Shots 18 and 19 disrupted (at 1.1 and .8 sec) probably because of RF.

Scorecard:

19 shots
5 fizzles
14 plasmas
0 duds

_________________________________________________


990909001 Plasma going to 1.86 sec. No real RF on this shot.
EF1_l supply went off just before the end of the shot at 1.83 sec - reason unknown.

PCS changes for next shot: none

990909002 Plasma going to 1.87 sec. RF maximum - 1.2 MW. EF H-mode from .84 to .92 sec.
Ohmic H-mode during rampdown (1.56 - 1.78 sec). EF1_l seems to be OK now.

PCS changes for next shot:
It turns out that the PCS was not loaded and we were running shot 990908020.
Loaded 990908006. TF should now invert at 1.5 sec instead of 1.6 sec.
Enabled Ar puff, pulse_gas1, programmed length - 25 msec.

990909003 Plasma. Two EF H-modes at .96 and 1.08 sec. RF max 1.5 MW (J3&4 and D together)

PCS changes for next shot:
The prepuff was programmed higher on this shot than on previous one and
there is a slight hesitation in current rise.
Reduced the prepuff from 20 msec to 18 msec

990909004 Plasma. 3 RF H-modes + 1 ohmic at rampdown.

PCS changes for next shot:
Reprogrammed R_XL and Z_XL to get rid of x-point drift towards inner nose.

990909005 Plasma. 3 RF H-modes (EF/EDA ?)
Z_XL and R_XL are constant to 1.5 sec.

PCS changes for next shot: none

990909006 Plasma. 3 RF H-modes (EDA ?)

PCS changes for next shot: none

990909006 Reduced RCUR to .6675 from .669 to increase the right gap to 11 mm

PCS changes for next shot: none

990909007 PLasma, 3 (EDA ?) H-modes. RF to 2.5 MW.

PCS changes for next shot: none

990909008 Plasma. 3 EDA ? H-modes. Right gap is around 1 cm.
Still some hesitation in current rise, but Br and Bz are jumping
around from shot to shot and seem to be irrelevant.

PCS changes for next shot:
Reduced prepuff to 16 msec

990909009 Plasma. Multiple short H-modes, RF around 2 MW.
Current rise is better.

PCS changes for next shot: none

990909010 Plasma. 2 small H-modes, RF around 2 MW

PCS changes for next shot: none

990909011 Fizzle.
SPANA crashed right after the shot.

PCS changes for next shot:
Restarted PCS, loaded from 990909010.
NO PCS changes.

990909012 Plasma. Small H-modes, RF around 2 MW.

PCS changes for next shot: none

990909013 Plasma disrupted at .93 sec due to large injection 4 msec after L-H
transition

PCS changes for next shot: none

990909014 Fizzle.

PCS changes for next shot:
Make Br 1 mT more negative.

990909015 Fizzle.

PCS changes for next shot:
Add 2 msec of prepuff

990909016 Fizzle.
Breakdown is at the right time.

PCS changes for next shot:
Return Br back (1 mT up) and set EF4 to -1285 from -1275.

990909017 Fizzle.

PCS changes for next shot:
Reduced RCUR offset from 5500 to 4500.

990909018 Plasma. Disrupted at 1.1 sec.

PCS changes for next shot: none

990909019 Plasma. Disrupted at .8 sec after going into H-mode.

Session Leader Comments

Physics Operator Comments
Sep 9 1999 09:06:24:640AMDmitri MossessianRun Plan and Engineering Setup for 990909:

SL: Wukitch/Schilling
PO: Mossessian

This run will be a continuation of that scheduled for September 8, 1999.
The general purpose will be to condition the RF antennas.

The run is scheduled to start at 10:00 and end at 17:00

Engineering setup:

Two hours ECDC in D2 prior to run, finishing at least 1 hour before run.

Setup power supplies from 990908004

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid DISABLED
fill B-side upper with 6 psi of H2 Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid enabled
J-bottom pumped out Hybrid DISABLED



PCS setup: Loaded shot 990908006. Coldstart OK.
Sep 9 1999 11:27:35:950AM990909001Dmitri MossessianPlasma going to 1.86 sec. No real RF on this shot.
EF1_l supply went off just before the end
of the shot at 1.83 sec - reason unknown.

No changes for next shot.
Sep 9 1999 11:54:50:357AM990909002Dmitri MossessianPlasma going to 1.87 sec. RF maximum - 1.2 MW. EF H-mode from .84 to .92 sec.
Ohmic H-mode during rampdown (1.56 - 1.78 sec)
EF1_l seems to be OK now.

It turns out that the PCS was not loaded and we were running shot 990908020.
Loaded 990908006. TF should now invert at 1.5 sec instead of 1.6 sec.
Enabled Ar puff, pulse_gas1, programmed length - 25 msec.

Sep 9 1999 12:12:05:577PM990909003Dmitri MossessianPlasma. Two EF H-modes at .96 and 1.08 sec.
RF max 1.5 MW (J3&4 and D together)

The prepuff was programmed higher on this shot than on previous one and
there is a slight hesitation in current rise.
Reduced the prepuff from 20 msec to 18 msec
Sep 9 1999 12:41:06:060PM990909004Dmitri MossessianPlasma. 3 RF H-modes + 1 ohmic at rampdown.

Reprogrammed R_XL and Z_XL to get rid of x-point drift towards inner nose.
Sep 9 1999 01:01:59:500PM990909005Dmitri MossessianPlasma. 3 RF H-modes (EF/EDA ?)
Z_XL and R_XL are constant to 1.5 sec.

No PCS changes for next shot.
Sep 9 1999 01:16:12:513PM990909006Dmitri MossessianPlasma. 3 RF H-modes (EDA ?)

No PCS changes for next shot.
Sep 9 1999 01:22:16:297PM990909006Dmitri MossessianReduced RCUR to .6675 from .669 to increase the right gap to 11 mm
Sep 9 1999 01:40:55:310PM990909007Dmitri MossessianPLasma, 3 (EDA ?) H-modes. RF to 2.5 MW.
NO PCS changes.
Sep 9 1999 01:52:30:607PM990909008Dmitri MossessianPlasma. 3 EDA ? H-modes. Right gap is around 1 cm.
Still some hesitation in current rise, but Br and Bz are jumping
around from shot to shot and seem to be irrelevant.
Reduced prepuff to 16 msec
Sep 9 1999 02:16:15:653PM990909009Dmitri MossessianPlasma. Multiple short H-modes, RF around 2 MW.
Current rise is better.

No PCS changes for next shot
Sep 9 1999 02:25:12:903PM990909010Dmitri MossessianPlasma. 2 small H-modes, RF around 2 MW
Sep 9 1999 03:06:36:700PM990909011Dmitri MossessianFizzle.
SPAN crashed right after the shot.

Restarted PCS, loaded from 990909010.
NO PCS changes.

Sep 9 1999 03:14:02:183PM990909012Dmitri MossessianPlasma. Small H-modes, RF around 2 MW.

No changes for next shot
Sep 9 1999 03:29:58:670PM990909013Dmitri MossessianPlasma disrupted at .93 sec due to large injection 4 msec after L-H
transition
Sep 9 1999 03:49:34:013PM990909014Dmitri MossessianFizzle.
Make Br 1 mT more negative.
Sep 9 1999 04:12:33:670PM990909015Dmitri MossessianFizzle.
Add 2 msec of prepuff
Sep 9 1999 04:25:08:687PM990909016Dmitri MossessianFizzle.
Breakdown is at the right time. Return Br back (1 mT up) and
set EF4 to -1285 from -1275.
Sep 9 1999 04:42:58:700PM990909017Dmitri MossessianFizzle.
Reduced RCUR offset from 5500 to 4500.
Sep 9 1999 04:54:23:387PM990909018Dmitri MossessianPlasma. Disrupted at 1.1 sec.

No PCS changes for next shot
Sep 9 1999 05:06:54:687PM990909019Dmitri MossessianPlasma. Disrupted at .8 sec after going into H-mode.

Engineering Operator Comments
ShotTimeTypeStatusComment
111:04:50:420AMPlasmaBadPlasma/faults on supplies 1 blown fuse EF1l
211:33:36:123AMPlasmaOkno faults/plasma
311:56:33:483AMPlasmaOkNo Faults
412:24:48:187PMPlasmaOkno faults
512:48:22:187PMPlasmaOkno faults
601:05:31:297PMPlasmaOkno faults/plasma
701:26:00:123PMPlasmaOkno faults/plasma
801:42:39:653PMPlasmaOkno faults/plasma
901:59:44:547PMPlasmaOkno faults/plasma
1002:19:44:903PMPlasmaOkno faults/plasma
1102:42:07:060PMPlasmaOkno faults/plasma
1203:07:03:530PMPlasmaOkno faults/plasma
1303:23:04:687PMPlasmaOkno faults/plasma
1403:42:30:293PMPlasmaOkno faults/fizzel
1503:58:04:903PMPlasmaOkno faults/fizzel
1604:13:40:047PMPlasmaOkno faults/fizzel
1704:27:46:843PMPlasmaOkNo Faults /fizzle
1804:45:01:250PMPlasmaOk(null)
1905:00:06:437PMPlasmaOk(null)