Alcator C-Mod Run 930723 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Gerry Tinios (shots 1-37)

Operators
Session leader(s):Gerry Tinios
Physics operator(s):Steve Horne
Engineering operator(s):Vinny Bertolino

Engineering Operator Run Comment
Higher currents

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries

Session Leader Comments
Jul 23 1993 08:56:28:790AMGerry TiniosToday's run features Horne as physics operator, Tinios as assistant operator,
Bertolino as engineering operator, Pierson on the state, Paranay on power,
Bosco on PLC and Sorci on aux. systems.
Aim: Learn how to use EFC for vertical control as per MP004.
Commuutation resistors: OH1A: 0.0001
OH1B: 0.045
OH2U: 0.0083
OH2L: 0.0085
EF1U: 0.0806
EF1L: 0.08
EF2U: 0.0455
EF2L: 0.0459
SUPPLY START CLOSE OPEN CROW INVERT
EF1L -1.1 -0.94 0.0 0.07 0.35
EF1U -1.1 -0.94 0.0 0.07 0.35
OH1 -1.1 -0.85 0.0 0.1 0.35
OH2L -1.1 -0.65 0.0 0.12 0.35
OH2U -1.1 -0.65 0.0 0.12 0.35
EF2L -0.4 0.35
EF2U -0.4 0.35
EF3 -0.05 0.35
EF4 -1.1 0.35
EFC -0.02 0.9
TF -1.5 0.5

Jul 23 1993 08:58:52:000AM930723001Gerry TiniosSame settings as shot 26 from yesterday.
B-side-upper for fueling. Pressure: 1.2e-5

Flash but no plasma.

Jul 23 1993 09:22:15:910AM930723002Gerry TiniosBz was slightly too positive in shot 1. Reduce EF4 for this shot by 50 A.
Also change EF4 volt-preprog so it is 0 for 0.5 sec before commutation.

Nothing.

Jul 23 1993 09:39:28:780AM930723003Gerry TiniosBz went too far negative. Add 30 A back to EF4.
Also set the curr-preprog to its t=0 value from t=-0.5 sec
so as to enter the shot with a flat current trace.
Raise pressure to 1.6e-5.

Flash.

Jul 23 1993 09:57:57:910AM930723004Gerry TiniosReduce EF4 by 30 A again, but keep curr_preprog flat as we enter shot.

Fizzle again.

Jul 23 1993 10:07:49:440AM930723005Gerry TiniosNo clues as to why we are not breaking down ==> reduce pressure to 1.1e-5.

Plasma. 440kA, looks a lot like 930722026.

Jul 23 1993 10:22:40:020AM930723006Gerry TiniosSame as previous shot, but chopper comes on at 30 msec.
Also Ar gas pulse was enabled.

Fizzle. Chopper bank charged, but we got no current on EFC.

Jul 23 1993 10:49:22:580AM930723007Gerry TiniosTurn off EFC-TMX. Reduce pressure to 9.e-6.
This is an attempt to get the plasma back.

Plasma. Saw sparks, but there do not seem to be any hard X-rays.
460kA, round plasma. Video does not show sparks.

Jul 23 1993 11:04:32:110AM930723008Gerry TiniosRaise pressure to 1.e-5.
Ar gas pulse increased by 2 msec
Turn chopper back on at 300 V static volt. We still don't know why it failed two
shots ago.

Got plasma and current on EFC. Plasma died earlier .

Jul 23 1993 11:17:00:830AM930723009Gerry TiniosAr gas pulse shortened by 4 msec. The consensus is that
we were limited by radiation from Moly and Argon in the previous shot.
500 V static voltage.

Nothing.

Jul 23 1993 11:22:34:610AM930723010Gerry TiniosPressure increased to 1.4e-5.
Chopper is hooked to wire 3, the second Z_cur predictor.

Fizzle.

Jul 23 1993 11:35:57:130AM930723011Gerry TiniosArgon pulse disabled.
Gas pressure reduced to 1.2 e-5.
EFC gain raised at 100 msec.

Fizzle.

Jul 23 1993 11:47:06:400AM930723012Gerry TiniosReduce pressure to 1.0e-5.

Got plasma.

Jul 23 1993 12:00:52:310PM930723013Gerry TiniosAll power supply invert-times that were 0.35 were changed to 0.45
in an attempt to prolong the life of the plasma.
Argon pulse enabled. Pulse starts at -50 msec and lasts 10 msec.

Nice long plasma.

Jul 23 1993 12:41:20:980PM930723013Gerry TiniosCORRECTION: Argon pulse starts at +50 msec.

Jul 23 1993 12:11:51:840PM930723014Gerry TiniosWire 3 (EFC) controller gain was rased at 100 msec.

Fizzle. Late breakdown.

Jul 23 1993 12:23:35:270PM930723015Gerry TiniosEF1U and EF1L curr-preprog was extended so as
to prolong the plasma.

Long plasma, dies at 400 msec.

Jul 23 1993 12:40:36:890PM930723016Gerry TiniosChange OH2 voltage programming to hold OH2 current up longer.
Doubled the controller gain on wire 3.
Argon puff at 50 msec was shortened.

Long plasma, dies after 420 msec.

Jul 23 1993 12:59:43:190PM930723017Gerry TiniosOH1 voltage programming was changed, so OH1 current stays on longer.
Increase EFC voltage to 650 V.

Plasma. Z-oscillation. Dies going up after 400 msec.

Jul 23 1993 01:17:25:700PM930723018Gerry TiniosMove all invert times to 0.5 sec.
Change TF invert time to 0.55sec.
Add derivative gain (one unit) to wire 3 at 0.2 sec.

Fizzle.

Jul 23 1993 01:33:31:970PM930723019Gerry TiniosExact repeat of previous shot.

Plasma. Dies of vertical instability.

Jul 23 1993 01:41:46:510PM930723020Gerry TiniosTurn up derivative gain on wire 3 to two units.
Hoping to control the vertical ionstability.

Fizzle. Late breakdown.

Jul 23 1993 01:59:00:910PM930723021Gerry TiniosRepeat previous shot.
Ar puff was extended by 2 msec.

Plasma. Still shaking up and down by 1cm. Density is dropping.

Jul 23 1993 02:07:19:840PM930723022Gerry TiniosRepeat previous shot.

Much like the last shot.

Jul 23 1993 02:20:12:820PM930723023Gerry TiniosDouble derivative gain on wire 3 (4 units).
Double proportional gain on wire 2 (the slow zcur feedback wire)
from 0.4 to 0.8.

Fizzle.

Jul 23 1993 02:30:45:450PM930723024Gerry TiniosRepeat.

Plasma. Oscillations started earlier, at about the time we applied the
wire 2 gain (150 msec).

Jul 23 1993 02:41:14:370PM930723025Gerry TiniosReduced proportional gain on wire 2 to 0.3

No flash.

Jul 23 1993 02:51:02:400PM930723026Gerry TiniosReduced pressure to 8.0e-6.

No flash.

Jul 23 1993 03:07:05:860PM930723027Gerry TiniosIncrease pressure to 1.2e-5.

No flash.

Jul 23 1993 03:26:47:930PM930723028Gerry TiniosRepeat of previous shot.

Fizzle.

Jul 23 1993 03:37:34:970PM930723029Gerry TiniosReduce pressure to 1.0e-5.

Got plasma. The oscillation in Z seems to be gone.

Jul 23 1993 03:48:37:600PM930723030Gerry TiniosSmoothed out the jump in gas-puff-2 at 0.3 sec. It seemed to
be causing some unpleasant things.

Fizzle.

Jul 23 1993 03:59:53:980PM930723031Gerry TiniosIncreased EF4 current-programming by 20 A. It was observed that
Bz has been slowly decreasing during the day by 2mT.

Fizzle.

Jul 23 1993 04:13:45:570PM930723032Gerry TiniosRepeat of previous shot.

Arcs, sparks and runaways. But it was a record shot in two ways.
Peak current: 0.5 MA
Duration: 520 msec

Jul 23 1993 04:26:08:670PM930723033Gerry TiniosReduce EF4 current by 10 A.
Increase fill pressure to 1.2e-5.

Plasma. Almost a runaway shot. High current and duration.

Jul 23 1993 04:37:19:930PM930723034Gerry TiniosIncrease EF2L current programming by 150 A later in the shot.
This is an attempt to cancel the bias field of the chopper and pull the
plasma down.

Plasma with lots of hard X-rays.

Jul 23 1993 04:47:32:800PM930723035Gerry TiniosReduce EF4-current programming by 10 A.

Plasma with hard X-rays again.

Jul 23 1993 04:59:09:150PM930723036Gerry TiniosAdjusted gas puffing so as to get a little more gas at the beginning.
A zcur predictor was put on wire 4 and hooked to the EFC with the
controller at maximum gain and a P-gain of 5 being turned on at 180 msec.

Plasma. No hard x_rays. Z-centroid slowly drifts down during shot.

Jul 23 1993 05:11:21:860PM930723037Gerry TiniosIncreased EF2L late current-programming by another 100 A to 1000A.

Plasma. No hard x_rays. Z-position drifted down later in the shot,
but still remained above the midplane.

Physics Operator Comments

Engineering Operator Comments
ShotTimeTypeStatusComment
108:55:13:470AMPlasmaOkno faults
209:16:48:500AMPlasmaOkno faults
309:29:31:000AMPlasmaOkno faults
409:43:06:890AMPlasmaOkno faults
510:00:01:800AMPlasmaOkno faults
610:13:05:740AMPlasmaOkno chopper all others no faults
710:27:36:640AMPlasmaOkno faults
810:56:58:700AMPlasmaOkno faults chopper ok
911:08:09:080AMPlasmaOkno faults
1011:19:36:150AMPlasmaOkno faults
1111:30:53:600AMPlasmaOkno faults
1211:41:58:820AMPlasmaOkno faults
1311:53:00:420AMPlasmaOkno faults
1412:04:33:040PMPlasmaOkno faults
1512:15:21:270PMPlasmaOkno faults
1612:34:49:110PMPlasmaOkno faults
1712:49:25:160PMPlasmaOkplasma ok
1801:10:36:690PMPlasmaOkno faults
1901:20:50:920PMPlasmaOkno faults
2001:35:11:980PMPlasmaOkno faults
2101:45:05:020PMPlasmaOkno faults
2202:01:15:440PMPlasmaOkno faults
2302:13:36:560PMPlasmaOkno faults
2402:23:44:400PMPlasmaOkno faults
2502:34:51:570PMPlasmaOkno faults
2602:45:55:470PMPlasmaOkno faults
2702:58:11:960PMPlasmaOkno faults
2803:09:05:650PMPlasmaOkno faults
2903:29:13:780PMPlasmaOkno faults
3003:41:11:850PMPlasmaOkno faults
3103:53:06:610PMPlasmaOkno faults
3204:03:26:070PMPlasmaOkno faults
3304:18:12:150PMPlasmaOkno faults
3404:30:40:300PMPlasmaOkno faults
3504:41:06:870PMPlasmaOkno faults
3604:52:17:760PMPlasmaOkno faults
3705:02:56:170PMPlasmaOkno faults