Alcator C-Mod Run 1020626 Information

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Miniproposals
Miniproposal:298a
Date Filed: 5/20/2002
Title:C-Mod Plasma Startup
First Author:Jim Irby
Session Leader:Jim Irby (shots 1-27)

Operators
Session leader(s):Jim Irby
Physics operator(s):Steve Wolfe
Engineering operator(s):Bill Parkin,Gary Dekow

Engineering Operator Run Comment
Continuation of MP 298A; PO: Irby; SL:Wolfe; EO:Dekow/Parkin

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:28:993PM
Author: To Be Determined
Run Summary for Wed. 26-JUN-2002

MP#298A: Startup/conditioning
SL: Wolfe
PO: Irby
EO: Dekow,Parkin

Plan:

We will continue cleanup of the machine with double null
plasmas. Some shots will be taken at higher densities to
check H-to-D ratios under more standard run conditions.

Begin testing of j-port as soon as reliable
plasmas are produced.

Evaluate lack of linearity in fluxihh RXL,... predictors;
try to identify a better scheme for control of high triang.
discharges.

Results: Lots of fizzles, but a higher percentage of plasmas than the last
couple runs. Got more upper and double null cases, on the ef1 shelves.

We put in some dummy predictors on wires 9-12 for the xpoint quantities, and
demonstrated that using 1020625024 @1.0sec and rxl=0.52m gives a better
response than the default predictor for rxl, but still has a response about
a factor of 2 below what it should be. This was present for shot#5 on; see
plasma shots 9,10, 16,17,22-24,27.

Brian puffed from the upper chanber on the last few shots, and we again tried
the pumps closed off in pulse on shots 26 and 27; 26 fizzled but 27 was good,
so we should get a good inventory accounting.

RF tried one vacuum conditioning shot, before 13, and we got the only dud of
the day, so we had them turn off from then on.

Increasing rcur offset in seg1 from 5500 to 6500 may have helped with fizzles
starting with shot #20, but it didn't eliminate them. May want to raise this
more. Ian worked over his init scope to take out an offset effect on RCUR and
ZCUR in the fluxihh predictor signals.

Scorecard:
Tests 2 (no power shots)
Duds 1
fizzles 13
plasmas 11
======= ==
shots 27


Physics Operator Summaries
Entered: Jul 7 2004 04:37:15:130PM
Author: To Be Determined
Physop Summary for 1020626: Plasma Conditioning and First RF Tests

SL: Wolfe
EO: Dekow/Parkin
PO: Irby

The first two shots of the day ran, but with disruptions late in the
discharge. Both showed a nice decrease in the density throughout the
shot. So we have removed inventory from the wall over the last couple
of days. However, when we raised the density from 3e19 to 1e20/m^2, we
still had H-to-D ratios of 30 to 35%. We need to run in a lower
null configuration to verify what the H-to-D is in our more standard
configuration.

We worked with RXU and ZXU to continue development of the double null
configuration. We can now produce very good double nulls with very
high triangularity.

Shot 13 was a dud very likely caused by the j-port rf vacuum conditioning
pulse just before the shot. This shot was followed by 2 fizzles.

Bob Granetz now has the new lower inner divertor halo current Rogowskis
operational.

Brian LaBombard successfully ran the e-top and bc-top capillaries. Some
initial experiments needed to help understand the fueling/pumping
issues for the new cryopump were begun. Modifications to the PLC
allowed the pumping stack gatevalves to close without shutting any of
the diagnostic gatevalves. I think we got some valuable information
on the last three shots using this new tool.


Score:

Duds 13 1

Fizzles 03,04,05,07,08,11,12,14,15,18,19,25,26 13

Plasmas 01,02,09,10,16,17,20,22,23,24,27 11

Data System Hangs 06 1
CAMAC problems 21 1

Session Leader Comments
Jun 26 2002 08:54:01:817AM1020626001Steve WolfeShot#1: Yesterday it became apparent that the fluxihh xpoint predictors
are out of their linear range on these high triangularity shots. Example
is 1020625024, where both the predictor and the fluxihh rxl in the analysis
tree show a nearly flat waveform, as requested, while efit and mfil show
rxl ramping in by several cm during the shot.

For shot#1, set up zero-gain predictors on wires #9-12, with rxl,zxl using
reference point rxl=0.52 instead of the default 0.564; and rxu,zxu with
reference point rxu=0.50 instead of the default 0.564.

Unfortunately, the request waveforms are linked to the active ones, so I can't
get a clean result. I need to see if there is some way to unlink these.
Jun 26 2002 09:29:54:230AM1020626001Steve WolfeIt looks like the rxl predictor with the ref point at .52
is showing the slope better than the nominal one. The apparent
error goes from 25000 at 0.5sec to 11000 at 1.4sec, which corresponds to
a motion of about 1.75cm. The wire 5 error is ~0 and flat.
Unfortunately, this is an upper null case where the lower xpoint
is partly out of the vessel so I can't compare well to EFIT.

Jun 26 2002 09:50:30:277AM1020626002Steve Wolfeshot#2: efit says rxl is moving in from 56cm to 48.5cm,
the fluxihh predictor shows a motion of only 12000, which
converts to 1.5cm (12000/8e5).

However, I'm looking at the error and the demand does not
get to flattop until .7sec, so I need to look more carefully
The predictor drops by about 9000, while the efit trace
moves by 2.5cm over the same time, so the predictor is off
about a factor 2.
Jun 26 2002 10:32:23:340AM1020626005Steve WolfeFor shot#5, recall the predictor for rxl using rxl=.52, shot=1020625024,time=1.0
The max factor drops from 7e-5 to 4.6e-5, but we were using 4e-5 anyway.

result: fizzle. Can't see the effect without a plasma
Jun 26 2002 12:38:03:583PM1020626010Steve Wolfeshot 10: another traq2 failure. Recover it and re-run efit
Jun 26 2002 01:07:51:107PM1020626013Steve WolfeShot#13: before this shot, RF did a test shot, raised pressure from
6e-7 onto the e-6 scale.

dud.
Jun 26 2002 02:13:54:977PM1020626016Steve Wolfeshot#16: nice upper null, several injections.
H/D 0.4, with density ~5e19, some gas from the valve.

next shot: raise nl04 demand
Jun 26 2002 02:36:25:873PM1020626017Steve Wolfeshot#17: got nl01 of 1.2e20 or so. upper null again
next shot: move rxu out to scour more of upper shelf
Jun 26 2002 02:59:56:113PM1020626019Steve Wolfeshot#19: fizzle; definitely bounced outside.
next shot: Irby changed rcur offset 5500->6500 to try to catch it.
Jun 26 2002 03:42:46:167PM1020626020Steve Wolfeshot#20: plasma to 1.66sec
Jun 26 2002 03:43:12:463PM1020626021Steve Wolfeshot#21: no power shot, camac hiway problem
Jun 26 2002 03:45:44:547PM1020626021Steve Wolfeshot#22: plasma to 1.73sec or so.
hard xrays on the tv. early bounce.
Jun 26 2002 04:10:42:010PM1020626023Steve Wolfeshot#23: Fizzle off moved to 1.8sec so Bob can see the disruption.
Brian will puff from upper capilary.
plasma to 1.72sec, nearly dn, mostly upper.
traq2 error again; re-run efit.
Jun 26 2002 04:26:01:797PM1020626024Steve Wolfeshot#24: repeat, bigger puff from labombard.
plasma 1.68sec, no density response to the puff, but Blab sees it on the
MKS.
Jun 26 2002 04:38:44:013PM1020626025Steve Wolfeshot#25: repeat; fizzle
Jun 26 2002 04:53:34:970PM1020626026Steve Wolfeshot#26: brian to puff elsewhere. pumping Gate valves to close in pulse
another fizzle.

next shot: raise Bz0 and try again
Jun 26 2002 05:05:02:127PM1020626027Steve Wolfeshot#27: plasma to 1.65 sec. gate valves closed successfully.
good shot to leave on the drum.

Physics Operator Comments
Jun 26 2002 07:42:43:390AMJim IrbyDid cold start:

rtnode -- data loaded, A matrix responds
rtnode -- data loaded, M matrix responds
rtnode -- data loaded, PID matrix responds
RT_NODE Done
26-JUN-2002 07:21:45.94


Jun 26 2002 09:29:11:743AM1020626001Jim IrbyModified ZCUR from 1020625026 to extend the +0.01 m value beyond 1.1 to 1.3 s

Added many features in segment 2 for Steve Wolfe: monitoring wires: wires 8 through 12 modified

Plasma into just into rampdown with first disruption for Bob to look at

Density actually going down during the shot ---- low of 3e19/m^2

CII at .004

Lost tangential VB ---- someone hit Earl's mount again?

EFIT indicates strong upper null moving into the wall --- good for cleaning?

H-to-D generally low at 20 to 30% but with spikes to 80%
Jun 26 2002 09:45:52:513AM1020626002Jim IrbyWill repeat --- will density drop more?

Disruption at 1.33 s --- will move ZCUR back down for next shot --- it went up

Density continues to drop

Jun 26 2002 09:58:07:030AM1020626003Jim IrbyZCUR from 0.01 back 0.00 m. May help disruption?

Fizzle: CII up to 0.015 -- dirt from disruption

Jun 26 2002 10:35:12:583AM1020626004Jim IrbyAnother fizzle

Carbon II still high at .013

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): 2.3289 -15.8302 -31.4179 -26.2295
dIp/dt (kA/ms): -1.7804 -3.3087 -1.4012 -0.0022
pressure (mTorr): 0.0688 0.0696 0.0680 0.0658
Bz0 (mT): -3.1020 -1.8627 0.0702 16.0417
Br0 (mT): 0.1346 -0.3095 -0.6802 -0.5825

Jun 26 2002 10:46:56:000AM1020626005Jim IrbyFizzle again

Will run ECDC 10 minutes before next shot


Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): -0.2652 -15.8302 -28.8010 -23.6127
dIp/dt (kA/ms): -1.7816 -2.9260 -1.5273 0.0010
pressure (mTorr): 0.0673 0.0688 0.0673 0.0622
Bz0 (mT): -2.9335 -0.5014 1.5333 17.3407
Br0 (mT): -0.1013 -0.2931 -0.3692 -0.9297

Note big jump in Bz0 from last shot ---- no PCS changes
Jun 26 2002 11:42:54:550AM1020626007Jim IrbyNo PCS changes ---- 10 minutes of ECDC before shot

Fizzle --- startup may look a little better --- will continue ECDC
Jun 26 2002 11:53:57:653AM1020626008Jim IrbyFizzle --- still better, but....


Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): 2.3062 -13.2588 -28.8010 -23.6354
dIp/dt (kA/ms): -1.6544 -3.1780 -1.9096 -0.1317
pressure (mTorr): 0.0703 0.0688 0.0696 0.0629
Bz0 (mT): -0.7907 0.5429 2.6804 19.3539
Br0 (mT): -0.3714 -0.3643 0.1911 -0.5938
Jun 26 2002 12:15:22:970PM1020626009Jim IrbyEF4 from -1325 to -1340 --- lots of variation in Bz0 from shot to shot, but it was high on shot 008

Plasma well into rampdown

We did get Bz0 down some:

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): 2.3289 -13.2360 -28.8010 -75.4959
dIp/dt (kA/ms): -1.4000 -3.1792 -3.0508 -5.5941
pressure (mTorr): 0.0680 0.0688 0.0673 0.0575
Bz0 (mT): -2.7896 -0.2213 1.1064 19.3056
Br0 (mT): -0.0559 -0.1868 -0.5791 -1.2432

Br0 also looks okay

H-to-D about 40%
Jun 26 2002 12:33:18:853PM1020626010Jim IrbyZXU from .02 to .01 m --- try to make it a little more double null

Plasma into rampdown

Carbon II down to .005

H/D 60%

Steve Wolfe reports upper triag at .9

Jun 26 2002 12:48:18:530PM1020626011Jim IrbySet NL04 gain back to 8 after 200 ms

NL04 request back to 5e19/m^2

Fizzle at 40 kA
Jun 26 2002 01:02:29:547PM1020626012Jim IrbyWent back to -1325 EF4 setting. Bz0 very low last shot

Bz0 jumps up again

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): 2.3289 -15.8075 -31.3952 -23.6127
dIp/dt (kA/ms): -1.5239 -3.4335 -3.5617 0.5063
pressure (mTorr): 0.0673 0.0680 0.0680 0.0562
Bz0 (mT): -2.3929 0.1097 1.2049 17.6690
Br0 (mT): -0.2645 -0.0736 -0.0961 -1.3798

Carbon II is low again at .004

Next will be gas tweaks
Jun 26 2002 01:13:47:917PM1020626013Jim IrbyGas from 25 to 30 ms

EF4 form -1325 to -1335 Amps

Dud --- we allowed J-Port to vacuum condition before this shot


Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): 2.3516 -15.8302 -21.0185 -21.0412
dIp/dt (kA/ms): -1.7804 -2.5456 -0.6359 -0.1283
pressure (mTorr): 0.0796 0.0805 0.0805 0.0805
Bz0 (mT): -2.5291 -0.6947 0.4896 16.1471
Br0 (mT): 0.1618 -0.5992 -0.1673 -0.7323

Got more gas as requested, Bz0 a little better
Jun 26 2002 01:43:36:813PM1020626014Jim IrbyNo PCS changes

ECDC for 10 minutes before shot

Fizzle --- CII up again

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): -0.2880 -15.8302 -26.2523 -23.6354
dIp/dt (kA/ms): -1.5237 -2.7976 -1.5271 -0.2576
pressure (mTorr): 0.0823 0.0833 0.0805 0.0736
Bz0 (mT): -1.7665 -0.3577 1.4565 17.2439
Br0 (mT): -0.0740 -0.8481 -0.3925 -0.9581

Jun 26 2002 01:54:28:167PM1020626015Jim IrbyNo PCS changes ---- 10 minutes of ECDC

Fizzle

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): -0.2880 -13.2588 -26.2068 -23.6354
dIp/dt (kA/ms): -1.5282 -2.7975 -1.7825 0.0001
pressure (mTorr): 0.0842 0.0833 0.0861 0.0778
Bz0 (mT): -2.0344 0.5641 1.9849 17.4695
Br0 (mT): -0.2788 -0.3156 -0.5304 -1.4533
Jun 26 2002 02:14:06:947PM1020626016Jim IrbyGas back to 25 ms from 30.

Nice plasma ---- video indicated something moving around on the lower outer shelf

H-to-D 40%

CII .005

Got the prefill we wanted. Bz0 and Br0 okay...

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): 2.3289 -13.2360 -28.8237 -72.9471
dIp/dt (kA/ms): -1.5248 -3.3086 -2.9259 -5.8518
pressure (mTorr): 0.0650 0.0673 0.0665 0.0568
Bz0 (mT): -2.4178 -0.8870 1.7259 17.9274
Br0 (mT): -0.1464 -0.9303 -0.6924 -1.2367
Jun 26 2002 02:17:43:360PM1020626016Robert GranetzSeveral of us saw a bright macroscopic object moving toroidally in the lower part
of the vessel. It seemed to me that it was during the flattop, and that it was
located on the outer shelf, but Steve Wolfe thought it was on the inboard wall.
Jun 26 2002 02:33:45:663PM1020626016Jim IrbyRaised density request from 5e19 to 1e20/m^2

Plasma for 1.69 s

Got requested density until 1.1 s or so

CII a little lower

H-to-D 32%

Jun 26 2002 02:43:50:810PM1020626018Jim IrbyChanges RXU from -.04 to -.03 m.

Fizzle

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): 2.3062 -15.8529 -31.4179 -26.2295
dIp/dt (kA/ms): -1.6554 -3.4312 -2.4161 0.2552
pressure (mTorr): 0.0696 0.0696 0.0688 0.0594
Bz0 (mT): -3.8379 -2.1503 -0.0484 15.4744
Br0 (mT): -0.4457 -0.6343 -0.2997 -1.0270

Bz0 jump again, but probably had nothing to do with fizzle.
Jun 26 2002 02:51:09:470PM1020626019Jim IrbyFizzle
Jun 26 2002 03:19:41:033PM1020626020Jim IrbyChanged seg 1 RCUR offset from 5500 to 6500 amps.

Plasma for 1.54 s

Looks like the RXU did change a little

H/D at 32% --- not very impressive

CII .005
Jun 26 2002 03:56:43:933PM1020626022Jim IrbyNo changes

Plasma for 1.73 s

H/D 30 to 40%
Jun 26 2002 04:14:36:973PM1020626023Jim IrbyPCS repeat

Brian will attempt to puff some gas from the e-top capillary: 16 t-l/s at 1 s
Last shot we had 8 mTorr in e-top --- how high will it go..

No change in e-top pressure

H/D 30 to 40%




Jun 26 2002 04:31:15:573PM1020626024Jim IrbyNo PCS changes

Brian is upping his e-top puff

Plasma

Brian may see a bump in e-top pressure

H/D peaking at 34%
Jun 26 2002 04:42:10:723PM1020626025Jim IrbyRepeat

Fizzle

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): -0.2880 -15.8302 -34.0120 -26.2295
dIp/dt (kA/ms): -1.6543 -3.3064 -2.1630 0.2521
pressure (mTorr): 0.0688 0.0688 0.0696 0.0608
Bz0 (mT): -3.8292 -1.8916 -0.4596 16.5525
Br0 (mT): -0.1711 -0.3840 -0.6874 -1.3018

Jun 26 2002 04:52:59:530PM1020626026Jim IrbyPCS repeat

Enable pump stack gatevalve closure

Fizzle??

Gatevalves worked properly during and right after shot. Some
diag gates closed well after shot however.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:01:45:883AMPlasmaOk
209:30:43:920AMPlasmaOk
309:49:29:493AMPlasmaOk
410:10:04:243AMPlasmaOk
510:30:22:540AMPlasmaOk
610:54:12:110AMPlasmaBadData System Problems
711:19:19:480AMPlasmaOk
811:41:01:017AMPlasmaOk
911:59:02:087AMPlasmaOk
1012:15:39:923PMPlasmaOk
1112:32:41:870PMPlasmaOk
1212:49:53:207PMPlasmaOk
1301:05:53:693PMPlasmaOk
1401:25:53:540PMPlasmaOk
1501:46:57:883PMPlasmaOk
1602:00:32:087PMPlasmaOk
1702:18:15:237PMPlasmaOk
1802:34:10:430PMPlasmaOk
1902:47:02:740PMPlasmaOk
2003:01:12:007PMPlasmaOk
2103:19:47:253PMPlasmaOkNo Power Shot
2203:40:51:380PMPlasmaOk
2303:58:30:670PMPlasmaOk
2404:16:47:510PMPlasmaOk
2504:31:43:497PMPlasmaOk
2604:45:29:700PMPlasmaOk
2705:01:17:933PMPlasmaOk