Alcator C-Mod Run 1030502 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Dmitri Mossessian (shots 1-25)
Session Leader:Steve Wukitch (shots 1-25)

Operators
Session leader(s):Dmitri Mossessian,Steve Wukitch
Physics operator(s):Dmitri Mossessian
Engineering operator(s): Unknown

Engineering Operator Run Comment
Continued startup, TS calibration by ECE cutoff, ICRF conditioning; SL M

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:37:17:660PM
Author: To Be Determined
Physop summary for Thursday, May 1, 2003
Run plan:

Continued startup, TS calibration by ECE cutoff, ICRF conditioning.

SL Mossessian, Wukitch

PO Mossessian

1. TS calibration. Run 4.0 T, density ramp up in L-mode to obtain ECE cutoffs in all ECE channels. 4 shots
should be enough, unless we ensounter unexpected problems

2. Return to 5.3 T. Continue ICRF conditioning

We'll start with a good discharge from May 1, then drop the field to 4 T, Current of 0.8 MA. Density should ramp from
8e20 to 2e20. We'll return to 5.3 T, nl=.8e20 after TS calibrations are completed.
____________________________________________________


Summary:

Good run, although not without problems. Started from shot 1030501006. TCI did
not work, so we tutned density feedback off and programed the PG3 to get the
required density. It did not work quite right on shot 1, but on shots 2 to 13
we got what we wanted. Using density ramp up and varying Bt between 4 and 3.5
T (see detailed list of shots) we obtained high quality ECE cutoffs for core
TS calibrations.
Before shot 5 the PO pushed the ready button before the PCS tree finished
loading. That caused severe problems with Hybrid. Coldstart had to be done to
make things run again. Then there was a problem with a switch in OH2 and some
arcing in a power supply. Shots 5,6,7,8 were duds and tests.
The second part of the run from shot 15 on was RF conditioning. Shot
1030501006 was loaded, thus returning to 5.4 T and density feedback. After
that the startup became less reliable. Shots 15 and 16 had lots of hard
x-rays. The startup seemed to improve when shot 1030502014 was loaded (with Bt
and Ip changed appropriately). The density feedback was restored for shot 18.
The plasma then ran reasonably well with occasional problems in startup. Shot
21 fizzled for no apparent reason - Bz was going up too slow when current
already reached 65 kA.

Total:

25 shots

20 plasmas
3 duds
1 test
1 fizzle

______________________________________________________

Details

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1030502001 mossessian PHYSICS_OPERATOR May 2 2003
10:04:46:580AM
. . . . . . . . . . . . . . . . . . . .
Load shot 1030501006. Run first shot at 5.3 T.
Due to problems with TCI we run without density feedback.

Programmed PG3 at 50 to 0.75 s and then ramping down slowly.
Turned off nl04 gain and controller.

Good shot. Gas puff was mistakenly turned on only at .65 s, so
plasma was feeding off the walls for the first half of the discharge.

Next shot - extended gas puff to 0. Field to 4 T (TF 111000 A)


----------------------------------------------------------------------------
1030502002 mossessian PHYSICS_OPERATOR May 2 2003
10:23:36:873AM
. . . . . . . . . . . . . . . . . . . .
Good shot. Density is nice and constant. Bt=4 T. ECE positions are perfect for
calibrations.

Next shot - start density ramp. PG3 up to 70 V from the beginning. The ramp
starts at .4 goes to 100 V at 2 s.
----------------------------------------------------------------------------
1030502003 mossessian PHYSICS_OPERATOR May 2 2003
10:37:24:973AM
. . . . . . . . . . . . . . . . . . . .
Good shot. Nice density ramp. Disrupted @1.29 s - probably density limit.

Next shot - go to 1 MA to increase density limit and heat plasma some more.
Slow down the ne ramp.
----------------------------------------------------------------------------
1030502004 mossessian PHYSICS_OPERATOR May 2 2003
10:59:55:350AM
. . . . . . . . . . . . . . . . . . . .
Good shot. Disrupted @1.48 s - probably density limit.

Next shot - try to slow ne ramp some more to avoid disruption. Add step in Bt
to 4.5 T @ 1.2 sec
----------------------------------------------------------------------------
1030502005 mossessian PHYSICS_OPERATOR May 2 2003
11:02:58:840AM
. . . . . . . . . . . . . . . . . . . .
Hybrid problems. No power shot
----------------------------------------------------------------------------
1030502007 mossessian PHYSICS_OPERATOR May 2 2003
12:45:11:576PM
. . . . . . . . . . . . . . . . . . . .
Dud. A switch in OH2 did not work.

----------------------------------------------------------------------------
1030502008 mossessian PHYSICS_OPERATOR May 2 2003
1:31:32:146PM
. . . . . . . . . . . . . . . . . . . .
Test
----------------------------------------------------------------------------
1030502009 mossessian PHYSICS_OPERATOR May 2 2003
1:31:39:286PM
. . . . . . . . . . . . . . . . . . . .
Good shot

Next shot - go to Bt=3.6 T (100 kA TF) and Ip=0.8 MA
----------------------------------------------------------------------------
1030502010 mossessian PHYSICS_OPERATOR May 2 2003
1:32:25:650PM
. . . . . . . . . . . . . . . . . . . .
Good shot

Next shot - go to 97 kA TF, modify PG3 to increase ne ramp rate slightly
----------------------------------------------------------------------------
1030502011 mossessian PHYSICS_OPERATOR May 2 2003
1:46:53:356PM
. . . . . . . . . . . . . . . . . . . .
Good shot

Next shot - add step up in Bt to 4 T at 1.1 s
----------------------------------------------------------------------------
1030502012 mossessian PHYSICS_OPERATOR May 2 2003
1:56:18:996PM
. . . . . . . . . . . . . . . . . . . .
Good shot

Next shot - go back to 4 T, 0.7 MA, constant nl=0.8e20 and fire a pellet
----------------------------------------------------------------------------
1030502013 mossessian PHYSICS_OPERATOR May 2 2003
2:13:57:913PM
. . . . . . . . . . . . . . . . . . . .
Good shot. Nice cutoffs from pellet

Next shot - go up in current to .85 MA
----------------------------------------------------------------------------
1030502014 mossessian PHYSICS_OPERATOR May 2 2003
2:50:09:343PM
. . . . . . . . . . . . . . . . . . . .
Good shot. Large pellet caused disruption
Next shot - give session beack to RF. Go to 5.4 T, 0.8 MA.
Load shot 1030501006
----------------------------------------------------------------------------
1030502015 mossessian PHYSICS_OPERATOR May 2 2003
2:51:02:063PM
. . . . . . . . . . . . . . . . . . . .
Plasma. Startup is not as good. Plasma bounced and lots of x-rays followed.

Next shot - no changes
----------------------------------------------------------------------------
1030502016 mossessian PHYSICS_OPERATOR May 2 2003
3:14:20:160PM
. . . . . . . . . . . . . . . . . . . .
Plasma. Same as shot 15

Next shot - load shot 1030502014. Changed Bt to 5.3, Ip to 0.8, left nl off
the feedback
----------------------------------------------------------------------------
1030502017 mossessian PHYSICS_OPERATOR May 2 2003
3:15:09:773PM
. . . . . . . . . . . . . . . . . . . .
Plasma. Good startup. No bounce, no x-rays

Next shot - change nl to TCI feedback
----------------------------------------------------------------------------
1030502018 mossessian PHYSICS_OPERATOR May 2 2003
3:36:56:963PM
. . . . . . . . . . . . . . . . . . . .
Plasma. Good startup.

Next shot - no changes
----------------------------------------------------------------------------
1030502019 mossessian PHYSICS_OPERATOR May 2 2003
4:18:52:510PM
. . . . . . . . . . . . . . . . . . . .
Plasma.

Next shot - no changes
----------------------------------------------------------------------------
1030502020 mossessian PHYSICS_OPERATOR May 2 2003
4:19:03:120PM
. . . . . . . . . . . . . . . . . . . .
Plasma.

Next shot - no changes
----------------------------------------------------------------------------
1030502021 mossessian PHYSICS_OPERATOR May 2 2003
4:20:12:623PM
. . . . . . . . . . . . . . . . . . . .
Fizzle. Current rises to 65 kA and suddenly bounces with no apparent reason.
Bz is rising slower than on shot 20 starting from .017 s

Next shot - no changes
----------------------------------------------------------------------------
1030502022 mossessian PHYSICS_OPERATOR May 2 2003
4:32:15:703PM
. . . . . . . . . . . . . . . . . . . .
Plasma. Bounces @ 0.013s but survives

Next shot - no changes
----------------------------------------------------------------------------
1030502023 mossessian PHYSICS_OPERATOR May 2 2003
4:35:46:553PM
. . . . . . . . . . . . . . . . . . . .
Plasma. Nice startup

Next shot - no changes
----------------------------------------------------------------------------
1030502024 mossessian PHYSICS_OPERATOR May 2 2003
4:50:28:230PM
. . . . . . . . . . . . . . . . . . . .
Plasma. Nice startup

Next shot - no changes



Session Leader Comments

Physics Operator Comments
May 2 2003 09:11:36:140AMDmitri MossessianRun Plan for Thursday, May 1, 2003

Continued startup, TS calibration by ECE cutoff, ICRF conditioning.

SL Mossessian, Wukitch

PO Mossessian

ENGINEERING SETUP

ECDC in D2 Overnight prior to run; 60 C Bake

Run Starts at 9:00 AM and Ends at 5:00 PM

Power Systems as on 1030429024

Gas setup:

Fill B-Top with 6 psi of 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)
fill C-side with 30 psi D2 Hybrid enabled (PG3)


ICRF off for the first half of the run - TS calibration

Enable the ECE and DNB gate-valves

Run plan:

1. TS calibration. Run 4.0 T, density ramp up in L-mode to obtain ECE cutoffs in all ECE channels. 4 shots
should be enough, unless we ensounter unexpected problems

2. Return to 5.3 T. Continue ICRF conditioning

We'll start with a good discharge from May 1, then drop the field to 4 T, Current of 0.8 MA. Density should ramp from
8e20 to 2e20. We'll return to 5.3 T, nl=.8e20 after TS calibrations are completed.


May 2 2003 10:04:46:580AM1030502001Dmitri MossessianLoad shot 1030501006. Run first shot at 5.3 T.
Due to problems with TCI we run without density feedback.

Programmed PG3 at 50 to 0.75 s and then ramping down slowly.
Turned off nl04 gain and controller.

Good shot. Gas puff was mistakenly turned on only at .65 s, so
plasma was feeding off the walls for the first half of the discharge.

Next shot - extended gas puff to 0. Field to 4 T (TF 111000 A)


May 2 2003 10:23:36:873AM1030502002Dmitri MossessianGood shot. Density is nice and constant. Bt=4 T. ECE positions are perfect for calibrations.

Next shot - start density ramp. PG3 up to 70 V from the beginning. The ramp starts at .4 goes to 100 V at 2 s.
May 2 2003 10:37:24:973AM1030502003Dmitri MossessianGood shot. Nice density ramp. Disrupted @1.29 s - probably density limit.

Next shot - go to 1 MA to increase density limit and heat plasma some more. Slow down the ne ramp.
May 2 2003 10:59:55:350AM1030502004Dmitri MossessianGood shot. Disrupted @1.48 s - probably density limit.

Next shot - try to slow ne ramp some more to avoid disruption. Add step in Bt to 4.5 T @ 1.2 sec
May 2 2003 11:02:58:840AM1030502005Dmitri MossessianHybrid problems. No power shot
May 2 2003 12:45:11:577PM1030502007Dmitri MossessianDud. A switch in OH2 did not work.

May 2 2003 01:31:32:147PM1030502008Dmitri MossessianTest
May 2 2003 01:31:39:287PM1030502009Dmitri MossessianGood shot

Next shot - go to Bt=3.6 T (100 kA TF) and Ip=0.8 MA
May 2 2003 01:32:25:650PM1030502010Dmitri MossessianGood shot

Next shot - go to 97 kA TF, modify PG3 to increase ne ramp rate slightly
May 2 2003 01:46:53:357PM1030502011Dmitri MossessianGood shot

Next shot - add step up in Bt to 4 T at 1.1 s
May 2 2003 01:56:18:997PM1030502012Dmitri MossessianGood shot

Next shot - go back to 4 T, 0.7 MA, constant nl=0.8e20 and fire a pellet
May 2 2003 02:13:57:913PM1030502013Dmitri MossessianGood shot. Nice cutoffs from pellet

Next shot - go up in current to .85 MA
May 2 2003 02:50:09:343PM1030502014Dmitri MossessianGood shot. Large pellet caused disruption
Next shot - give session beack to RF. Go to 5.4 T, 0.8 MA.
Load shot 1030501006
May 2 2003 02:51:02:063PM1030502015Dmitri MossessianPlasma. Startup is not as good. Plasma bounced and lots of x-rays followed.

Next shot - no changes
May 2 2003 03:14:20:160PM1030502016Dmitri MossessianPlasma. Same as shot 15

Next shot - load shot 1030502014. Changed Bt to 5.3, Ip to 0.8, left nl off the feedback
May 2 2003 03:15:09:773PM1030502017Dmitri MossessianPlasma. Good startup. No bounce, no x-rays

Next shot - change nl to TCI feedback
May 2 2003 03:36:56:963PM1030502018Dmitri MossessianPlasma. Good startup.

Next shot - no changes
May 2 2003 04:18:52:510PM1030502019Dmitri MossessianPlasma.

Next shot - no changes
May 2 2003 04:19:03:120PM1030502020Dmitri MossessianPlasma.

Next shot - no changes
May 2 2003 04:20:12:623PM1030502021Dmitri MossessianFizzle. Current rises to 65 kA and suddenly bounces with no apparent reason.
Bz is rising slower than on shot 20 starting from .017 s

Next shot - no changes
May 2 2003 04:32:15:703PM1030502022Dmitri MossessianPlasma. Bounces @ 0.013s but survives

Next shot - no changes
May 2 2003 04:35:46:553PM1030502023Dmitri MossessianPlasma. Nice startup

Next shot - no changes
May 2 2003 04:50:28:230PM1030502024Dmitri MossessianPlasma. Nice startup

Next shot - no changes
May 2 2003 05:01:29:997PM1030502025Dmitri MossessianPlasma.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:29:01:727AMPlasmaOk
210:06:48:427AMPlasmaOk
310:24:36:720AMPlasmaOk
410:39:51:337AMPlasmaOk
511:00:42:947AMPlasmaOk
611:23:01:073AMPlasmaOk
711:46:44:517AMPlasmaBadNo OH2U & L Current
812:48:21:160PMTestOkOH Commutation Test
901:02:24:790PMTestOk
1001:19:00:020PMPlasmaOk
1101:33:25:633PMPlasmaOk
1201:49:13:063PMPlasmaOk
1302:03:49:400PMPlasmaOk
1402:18:11:200PMPlasmaOk
1502:37:35:963PMPlasmaOk
1602:57:01:713PMPlasmaOk
1703:10:17:327PMPlasmaOk
1803:23:30:427PMPlasmaOk
1903:39:05:717PMPlasmaOk
2003:51:54:877PMPlasmaOk
2104:04:42:503PMPlasmaOk
2204:18:24:027PMPlasmaOk
2304:32:34:330PMPlasmaOk
2404:46:12:270PMPlasmaOk
2504:59:06:010PMPlasmaOk