Alcator C-Mod Run 1030422 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader: Unknown (shots 1-29)

Operators
Session leader(s): Unknown
Physics operator(s):Ian Hutchinson
Engineering operator(s):Ed Fitzgerald,Gary Dekow

Engineering Operator Run Comment
Plasma Startup

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:37:17:363PM
Author: To Be Determined
Physop Summary 1030422 Startup

PO Hutch
EO Dekow/Fitzgerald

Summary
_______

A good day for the first day of plasma shots. About 13 seconds of
plasma were obtained. A number of full rampdowns were achieved. Gas
puff was preprogrammed, not fed back. Carbon II levels were dropping
during initiation. Attempts to move the cleaning effect to the upper
chamber resulted in disruptions. The first was due to vertical
instability, but the second appeared to be due to greatly increased
fueling during double or upper null plasmas. These disruptions took
several shots to recover from. So we backed away and recovered long
plasma. Probably should try again in a day or so with an upper null
plasma that we know is ok.

Things learned. (Or relearned)
_______________

EF3 Voltage is a good way to tune the Bz ramp rate during initiation.
100V difference is a significant step.

Base pressure greater than about 7e-7 after a disruption is too much
and the initiations are choked. After a plasma shot, one can tolerate
up to about 1e6.

Ip offset needs to be about -30000, and the OH2 voltage needs to be
drawn at about 25V to minimize the current error.

Scorecard
_________

Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax
1 0.000 0.021 2 0.363 0.667
3 0.000 0.023 4 0.000 0.025

8 0.090 0.250
9 0.000 0.027 10 1.611 0.776
11 0.000 0.025 12 0.123 0.360
13 1.794 0.780 14 0.000 0.033
15 1.849 0.781 16 1.892 0.781
17 0.000 0.040 18 1.902 0.767
19 1.258 0.855 20 0.000 0.032
21 0.000 0.031 22 0.000 0.033
23 0.000 0.041 24 0.927 0.776
25 0.000 0.025 26 0.000 0.027
27 0.178 0.299 28 1.813 0.782
29 0.000 0.042

26 Attempts: 12 plasmas. 13 fizzles. 1 Power-supply dud.


Details.
________

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1030422xxx hutch PHYSICS_OPERATOR Apr 22 2003 8:54:53:356AM
. . . . . . . . . . . . . . . . . . . .
Startup Activities


Starting from the successful shot 1030418035.
It had substantial gas puff in segment 1
which seems to have been more than it could swallow.
So reduce the preprogrammed puff
in segment 1 from a peak of 65 to about 38.

Also add a puff in segment 2 at about 0.6s in case we get there.

Load load/clean
----------------------------------------------------------------------------
1030422001 hutch PHYSICS_OPERATOR Apr 22 2003 10:00:37:193AM
. . . . . . . . . . . . . . . . . . . .
Dud. (power supply).

Bz and Br are badly wrong.
This is because the OH2s are not reaching their demands.
The Compare volts scope seems to show that Mout and the actual
voltage differ widely.

OH2 Limits were set incorrectly. Numbers were reversed.
Reset those and take another shot.
----------------------------------------------------------------------------
1030422002 hutch PHYSICS_OPERATOR Apr 22 2003 10:17:26:826AM
. . . . . . . . . . . . . . . . . . . .
Plasma to 0.35s

Density gets up to 1e20 nl04 by .25s. That seems too much.

Lower gas puff in segment 1 to 25.
----------------------------------------------------------------------------
1030422003 hutch PHYSICS_OPERATOR Apr 22 2003 10:24:06:513AM
. . . . . . . . . . . . . . . . . . . .
Fizzle.

CII 0.02 but other than that not a lot obvious.
Do nothing.
----------------------------------------------------------------------------
1030422004 hutch PHYSICS_OPERATOR Apr 22 2003 11:52:39:763AM
. . . . . . . . . . . . . . . . . . . .
Fizzle. Rather like the previous CII level.

EF4 to -1315 from -1325A.
----------------------------------------------------------------------------
1030422008 hutch PHYSICS_OPERATOR Apr 22 2003 12:03:02:086PM
. . . . . . . . . . . . . . . . . . . .
Plasma till .087s

Shots 5-7 were various igor tests and failures.

Rcur to .66 from .63 at .01s in segment 1
----------------------------------------------------------------------------
1030422009 hutch PHYSICS_OPERATOR Apr 22 2003 12:13:23:500PM
. . . . . . . . . . . . . . . . . . . .
Fizzle. Bz still rising too fast.

Take 100 V off EF3 V in first 20ms.
----------------------------------------------------------------------------
1030422010 hutch PHYSICS_OPERATOR Apr 22 2003 12:38:12:556PM
. . . . . . . . . . . . . . . . . . . .
Plasma till 1.6s.
Reasonable shot but a bit too much density at the end.
There's a transition at about 1.04s to a quieter radiation
signal and the density then seems to rise.

Reduce second gas puff duration.
----------------------------------------------------------------------------
1030422011 hutch PHYSICS_OPERATOR Apr 22 2003 12:49:15:193PM
. . . . . . . . . . . . . . . . . . . .
Fizzle.

No changes.
----------------------------------------------------------------------------
1030422012 hutch PHYSICS_OPERATOR Apr 22 2003 1:06:16:716PM
. . . . . . . . . . . . . . . . . . . .
Plasma till .12s. Very slow current rise. 300kA at .1s
Big injection at .11s

Lower the first gas puff some more.
----------------------------------------------------------------------------
1030422013 hutch PHYSICS_OPERATOR Apr 22 2003 1:23:17:723PM
. . . . . . . . . . . . . . . . . . . .
Plasma till 1.8s

No changes.
----------------------------------------------------------------------------
1030422014 hutch PHYSICS_OPERATOR Apr 22 2003 1:35:46:836PM
. . . . . . . . . . . . . . . . . . . .
Fizzle. Some signs that the CII is staying down.

Increase EF3 at 15ms by 100V.
----------------------------------------------------------------------------
1030422015 hutch PHYSICS_OPERATOR Apr 22 2003 1:51:16:360PM
. . . . . . . . . . . . . . . . . . . .
Plasma till 1.85s. Ramped down to 200kA.
Hard x-rays.

Insert Argon pulse at .3s of 25ms duration.
EF3V to 2450 at 5ms from 2400.
Base pressure 1.0e-6 at init.
----------------------------------------------------------------------------
1030422016 hutch PHYSICS_OPERATOR Apr 22 2003 2:06:59:710PM
. . . . . . . . . . . . . . . . . . . .
Plasma till 1.89s. Good ramp down.
Got rid of early bounce. CII is continuing down.

Change Ip offset to -13000 from -23000.
I put the Ar pulse on the wrong valve. Should be 1. Fixed.
1.0e-6 at init.
----------------------------------------------------------------------------
1030422017 hutch PHYSICS_OPERATOR Apr 22 2003 2:20:09:390PM
. . . . . . . . . . . . . . . . . . . .
Fizzle at 25kA gas current. Looks like an outboard bounce.

EF3V to 2100 from 1950 at 20ms.
----------------------------------------------------------------------------
1030422018 hutch PHYSICS_OPERATOR Apr 22 2003 2:34:56:473PM
. . . . . . . . . . . . . . . . . . . .
Plasma till 1.9s.

Ip offset to -30000 from -13000.

Zxu to 0. from +.02. RXU ramps to -.005 from -.02
zcur ramps to 0. This should be near to double null.
----------------------------------------------------------------------------
1030422019 hutch PHYSICS_OPERATOR Apr 22 2003 2:54:23:176PM
. . . . . . . . . . . . . . . . . . . .
Plasma till 1.3s. VDE.
Got double null and slightly upper before instability.
Base pressure remains very high after shot.

Adjust shape to try to make more stable and swing from
lower to upper null.
Increase OH2V during flat top to 20V.
Base pressure 2.0e-6 at init.
----------------------------------------------------------------------------
1030422020 hutch PHYSICS_OPERATOR Apr 22 2003 3:07:32:053PM
. . . . . . . . . . . . . . . . . . . .
Fizzle. CII=.006.
Gas current offset changed. This is probably an indication of
a change in the divertor resistance. The disruption shook things up.

Change nothing.
Base pressure 1.1e-6 at init.
----------------------------------------------------------------------------
1030422021 hutch PHYSICS_OPERATOR Apr 22 2003 3:20:08:510PM
. . . . . . . . . . . . . . . . . . . .
Fizzle. Rather similar.

EF3V to 2300 from 2400 at 12ms.
8.8e-7 at init.
----------------------------------------------------------------------------
1030422022 hutch PHYSICS_OPERATOR Apr 22 2003 3:35:13:830PM
. . . . . . . . . . . . . . . . . . . .
Fizzle. Nearly got it.

Br offset to .0017 from .002.
Base pressure 6.6e-7 at init.
----------------------------------------------------------------------------
1030422023 hutch PHYSICS_OPERATOR Apr 22 2003 3:50:04:823PM
. . . . . . . . . . . . . . . . . . . .
Fizzle.
Got to 20kA and bounced.

EF3V to 2400 from 2300 at 12ms.
----------------------------------------------------------------------------
1030422024 hutch PHYSICS_OPERATOR Apr 22 2003 4:05:10:720PM
. . . . . . . . . . . . . . . . . . . .
Plasma till 0.9. Vertical problem but also a lot of gas
This shot would probably go if not for the density being
too high.

Import segment 2 from shot 18.
Ip offset to -30000.
Base pressure 1.6e-6 at init.
----------------------------------------------------------------------------
1030422025 hutch PHYSICS_OPERATOR Apr 22 2003 4:13:30:640PM
. . . . . . . . . . . . . . . . . . . .
Fizzle.

OH2V to 20V in flat top.
Br offset to .0015.
----------------------------------------------------------------------------
1030422026 hutch PHYSICS_OPERATOR Apr 22 2003 4:31:12:026PM
. . . . . . . . . . . . . . . . . . . .
Fizzle (was about .8e-6 base pressure).


EF4 I to -1320 from -1315.
----------------------------------------------------------------------------
1030422027 hutch PHYSICS_OPERATOR Apr 22 2003 4:43:09:546PM
. . . . . . . . . . . . . . . . . . . .
Plasma to .175s. Ghastly resistive slow ramp.

Do nothing.
Base pressure 7.8e-6 at init.
----------------------------------------------------------------------------
1030422028 hutch PHYSICS_OPERATOR Apr 22 2003 5:01:09:323PM
. . . . . . . . . . . . . . . . . . . .
Plasma to 1.8s.

OH2V to 23V during flat top. Failed to load for this shot.
Base pressure 9.5e-7.
----------------------------------------------------------------------------
1030422029 hutch PHYSICS_OPERATOR Apr 22 2003 5:01:09:323PM
. . . . . . . . . . . . . . . . . . . .
Fizzle. Bounced at 25ka.

Session Leader Comments

Physics Operator Comments
Apr 22 2003 08:54:53:357AMIan HutchinsonStartup Activities


Starting from the successful shot 1030418035. It had substantial gas puff in segment 1
which seems to have been more than it could swallow. So reduce the preprogrammed puff
in segment 1 from a peak of 65 to about 38.

Also add a puff in segment 2 at about 0.6s in case we get there.

Load load/clean
Apr 22 2003 10:00:37:193AM1030422001Ian HutchinsonDud. (power supply).

Bz and Br are badly wrong.
This is because the OH2s are not reaching their demands.
The Compare volts scope seems to show that Mout and the actual
voltage differ widely.

OH2 Limits were set incorrectly. Numbers were reversed.
Reset those and take another shot.
Apr 22 2003 10:17:26:827AM1030422002Ian HutchinsonPlasma to 0.35s

Density gets up to 1e20 nl04 by .25s. That seems too much.

Lower gas puff in segment 1 to 25.
Apr 22 2003 10:24:06:513AM1030422003Ian HutchinsonFizzle.

CII 0.02 but other than that not a lot obvious.
Do nothing.
Apr 22 2003 11:52:39:763AM1030422004Ian HutchinsonFizzle. Rather like the previous CII level.

EF4 to -1315 from -1325A.
Apr 22 2003 12:03:02:087PM1030422008Ian HutchinsonPlasma till .087s

Shots 5-7 were various igor tests and failures.

Rcur to .66 from .63 at .01s in segment 1
Apr 22 2003 12:13:23:500PM1030422009Ian HutchinsonFizzle. Bz still rising too fast.

Take 100 V off EF3 V in first 20ms.
Apr 22 2003 12:38:12:557PM1030422010Ian HutchinsonPlasma till 1.6s.
Reasonable shot but a bit too much density at the end.
There's a transition at about 1.04s to a quieter radiation
signal and the density then seems to rise.

Reduce second gas puff duration.
Apr 22 2003 12:49:15:193PM1030422011Ian HutchinsonFizzle.

No changes.
Apr 22 2003 01:06:16:717PM1030422012Ian HutchinsonPlasma till .12s. Very slow current rise. 300kA at .1s
Big injection at .11s

Lower the first gas puff some more.
Apr 22 2003 01:23:17:723PM1030422013Ian HutchinsonPlasma till 1.8s

No changes.
Apr 22 2003 01:35:46:837PM1030422014Ian HutchinsonFizzle. Some signs that the CII is staying down.

Increase EF3 at 15ms by 100V.
Apr 22 2003 01:51:16:360PM1030422015Ian HutchinsonPlasma till 1.85s. Ramped down to 200kA.
Hard x-rays.

Insert Argon pulse at .3s of 25ms duration.
EF3V to 2450 at 5ms from 2400.
Base pressure 1.0e-6 at init.
Apr 22 2003 02:06:59:710PM1030422016Ian HutchinsonPlasma till 1.89s. Good ramp down.
Got rid of early bounce. CII is continuing down.

Change Ip offset to -13000 from -23000.
I put the Ar pulse on the wrong valve. Should be 1. Fixed.
1.0e-6 at init.
Apr 22 2003 02:20:09:390PM1030422017Ian HutchinsonFizzle at 25kA gas current. Looks like an outboard bounce.

EF3V to 2100 from 1950 at 20ms.
Apr 22 2003 02:34:56:473PM1030422018Ian HutchinsonPlasma till 1.9s.

Ip offset to -30000 from -13000.

Zxu to 0. from +.02. RXU ramps to -.005 from -.02
zcur ramps to 0. This should be near to double null.
Apr 22 2003 02:54:23:177PM1030422019Ian HutchinsonPlasma till 1.3s. VDE.
Got double null and slightly upper before instability.
Base pressure remains very high after shot.

Adjust shape to try to make more stable and swing from
lower to upper null.
Increase OH2V during flat top to 20V.
Base pressure 2.0e-6 at init.
Apr 22 2003 03:07:32:053PM1030422020Ian HutchinsonFizzle. CII=.006.
Gas current offset changed. This is probably an indication of
a change in the divertor resistance. The disruption shook things up.

Change nothing.
Base pressure 1.1e-6 at init.
Apr 22 2003 03:20:08:510PM1030422021Ian HutchinsonFizzle. Rather similar.

EF3V to 2300 from 2400 at 12ms.
8.8e-7 at init.
Apr 22 2003 03:35:13:830PM1030422022Ian HutchinsonFizzle. Nearly got it.

Br offset to .0017 from .002.
Base pressure 6.6e-7 at init.
Apr 22 2003 03:50:04:823PM1030422023Ian HutchinsonFizzle.
Got to 20kA and bounced.

EF3V to 2400 from 2300 at 12ms.
Apr 22 2003 04:05:10:720PM1030422024Ian HutchinsonPlasma till 0.9. Vertical problem but also a lot of gas
This shot would probably go if not for the density being
too high.

Import segment 2 from shot 18.
Ip offset to -30000.
Base pressure 1.6e-6 at init.
Apr 22 2003 04:13:30:640PM1030422025Ian HutchinsonFizzle.

OH2V to 20V in flat top.
Br offset to .0015.
Apr 22 2003 04:31:12:027PM1030422026Ian HutchinsonFizzle (was about .8e-6 base pressure).


EF4 I to -1320 from -1315.
Apr 22 2003 04:43:09:547PM1030422027Ian HutchinsonPlasma to .175s. Ghastly resistive slow ramp.

Do nothing.
Base pressure 7.8e-6 at init.
Apr 22 2003 05:01:09:323PM1030422028Ian HutchinsonPlasma to 1.8s.

OH2V to 23V during flat top. Failed to load for this shot.
Base pressure 9.5e-7.
Apr 22 2003 05:19:55:680PM1030422029Ian HutchinsonFizzle bounced at 25kA.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:43:34:077AMPlasmaOk
210:00:54:757AMPlasmaOk
310:13:28:710AMPlasmaOk
410:25:58:503AMPlasmaOk
511:15:29:133AMTestBad
811:48:36:880AMPlasmaOk
912:04:12:730PMPlasmaOk
1012:22:48:833PMPlasmaOk
1112:36:25:240PMPlasmaOk
1212:49:04:113PMPlasmaOk
1301:04:18:413PMPlasmaOk
1401:19:17:840PMPlasmaOk
1501:34:52:193PMPlasmaOk
1601:49:30:170PMPlasmaOk
1702:05:18:257PMPlasmaOk
1802:17:55:260PMPlasmaOk
1902:33:38:970PMPlasmaOk
2002:52:30:377PMPlasmaOk
2103:05:19:740PMPlasmaOk
2203:18:11:180PMPlasmaOk
2303:33:20:220PMPlasmaOk
2403:47:36:977PMPlasmaOk
2504:03:24:080PMPlasmaOk
2604:15:37:893PMPlasmaOk
2704:28:36:007PMPlasmaOk
2804:41:16:620PMPlasmaOk
2904:58:26:850PMPlasmaOk