Alcator C-Mod Run 1050506 Information

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Miniproposals
Miniproposal:417
Date Filed: 2/24/2005
Title:Plasma performance, boronization and ICRF heating effectiveness with high-Z antenna guards and all-m
First Author:Yijun Lin
Session Leader:Yijun Lin (shots 1-32)

Operators
Session leader(s):Yijun Lin
Physics operator(s):Steve Wolfe,Earl Marmar
Engineering operator(s):Andy Pfeiffer,Bill Byford,Bill Parkin

Engineering Operator Run Comment
Continue attempts to clean up and get full length pulses.Session leader:

Session Leader Plans
Entered: May 6 2005 09:04:18:050AM
Author: Yijun Lin
Get reliable plasmas first then continue on MP417.
Finish the original plan of 1050504.

Physics Operators Plans
Entered: May 5 2005 05:54:16:960PM
Author: Earl Marmar
Plan for Friday, May 6, 2005

Continue attempts to clean up and get full length pulses.

Engineering setup:

Session leader: Y. Lin/B. Lipschultz
Physics operator: E. Marmar

Overnight bake at 60 C. No ECDC.

Run begins at 09:00 and ends at 17:00.

Power systems as on 1050505022
A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and enabled.

Gas Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid DISABLED (PG1)
leave B-side upper alone, Hybrid disabled
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)

fill NINJA with 8 psi N2 Hybrid DISABLED.

Torvac setup: machine gate valves to remain open during and after shot.

Enable the following, assuming no vacuum problems:
ECE, VUV, Z-bolo shutters


Session Leader Summaries
Entered: May 9 2005 09:34:49:830AM
Author: Yijun Lin
Slow progress in getting plasmas. We have a few shots lasting for ~ 1 sec.
shot 25 and 32 were rather normal shots except the density was higher than
demanded (but it didn't rise as other shots).


Decision is to be made soon on whether and how to deal with
the apparent dust piles on the LH grill and how to recover plasma operation
with/without machine opening.

(Added on 1050509: A vacuum leak on the LH launcher
developed on 05/06 evening after the run prompted
the decision of pulling out the launcher from the machine. )

Physics Operator Summaries
Entered: May 6 2005 05:34:40:560PM
Author: Earl Marmar
Made some progress on the cleanup today. We started by running inner-wall limited plasmas, then switched to LSN for shot 21 on. Eventually we got to a plasma that made it into rampdown, shot 25, at 700 kA.

Note that the LSN shots were run from segment 3, not segment 2.

Startup was variable, and a lot of shots had severe hard x-ray fluxes.
Startup adjustments included increasing the prepuff (to 31 msec by the end), and making EF4 less negative before t=0.

Matt Reinke reported decreasing levels of Ti, particularly on the shots that were lasting the longest.

There were 3 power supply duds (1 no TF, 2 no OH1 commutation).

Summary:

2 fizzles
3 power supply duds
27 plasmas

32 data system cycles

Session Leader Comments
May 6 2005 09:42:47:363AM1050506001Yijun LinCurrent almost died at 0.5 sec but recovered.
Plasma till 0.7 sec.
Serious runaway.



May 6 2005 09:43:03:097AM1050506002Yijun LinPlasma till 0.45 sec. another runaway shot

May 6 2005 09:47:45:427AM1050506003Yijun Linfizzle
May 6 2005 10:01:24:223AM1050506004Yijun Linplasma till 0.7 sec. 600 kA. inner wall limited.

May 6 2005 10:19:19:113AM1050506005Yijun Lin plasma till 0.25 sec, 300 kA.
Camera data are back. Same stuff seen from the
inner wall and launcher in LH camera view.


May 6 2005 10:29:40:987AM1050506006Yijun Lin plasma to 0.91 sec. 600 kA.
Density rised after 0.82 sec, which killed the plasma

May 6 2005 11:04:44:020AM1050506008Yijun Linplasma till 0.998 sec, 750 kA. (longest and highest
current this week.) Ip programed to rise to 1 MA after 0.5 s
try some ICRF power in.
May 6 2005 11:08:41:003AM1050506009Yijun Linto 62 ms. Injections killed it.

May 6 2005 11:26:46:410AM1050506010Yijun Linplasma to 0.44 sec, 520 kA.
May 6 2005 11:42:31:283AM1050506011Yijun Lin plasma to 0.24 sec, 400 kA.

May 6 2005 12:00:09:550PM1050506012Yijun Lin plasma to 0.76 sec, 600 kA.
1 MW ICRF in from J antenna. Density rises after 0.6 sec, same time
as the ICRF coming up. (The rising density made the ICRF matching
nearly impossible).

May 6 2005 12:10:23:603PM1050506013Yijun Lin like shot 1. lots of runaway.
plasma to 0.66 sec. 500 kA. ICRF tripped out

May 6 2005 12:38:05:187PM1050506014Yijun Linplasma to 0.17 sec.
May 6 2005 12:37:36:357PM1050506015Yijun Linplasma to 0.21 sec, 540 kA.
May 6 2005 12:47:54:513PM1050506016Yijun Linplasma to 0.2 sec, 600 kA.

May 6 2005 01:11:44:547PM1050506017Yijun Linplasma to 1.1 sec, 0.7 MA.
ICRF ~ 1 MW from 0.6 to 0.8 sec.
Interesting lighting up of the sandpiles at frame 33 of
the LH view after the disruption.

May 6 2005 01:13:38:013PM1050506018Yijun Linplasma to 80 ms, 200 kA.
May 6 2005 01:29:26:467PM1050506019Yijun Lin plasma to 1.05 sec, 670 kA.
Tiny RF power. Density still rised.
May 6 2005 01:39:56:903PM1050506020Yijun Linplasma to 200 ms, 450 kA.
May 6 2005 01:57:01:153PM1050506021Yijun Lin plasma to 180 ms. 500 kA at 0.1 sec.


May 6 2005 02:08:15:843PM1050506022Yijun Lin plasma to 0.75 sec. LSN. Little RF in. density way too high.

May 6 2005 02:23:59:530PM1050506023Yijun Linplasma to 0.35 sec, 600 kA
May 6 2005 02:56:26:670PM1050506024Yijun Lin plasma to 0.42 sec, 600 kA
May 6 2005 03:15:31:983PM1050506025Yijun LinA normal shot. 700 kA. to 1.8 sec.
Density started rising only after 1.4 sec.
0.6 MW RF in from J antenna.
Divertor pressure stayed normal after the plasma.
It is the 131st shot this week.
May 6 2005 03:21:43:170PM1050506026Yijun Lindud. No TF
May 6 2005 03:36:04:700PM1050506027Yijun Lin plasma to 0.25 sec.
May 6 2005 03:50:50:140PM1050506028Yijun Lin plasma to 0.45 sec. 670 kA.
May 6 2005 04:18:14:437PM1050506029Yijun Lindud
May 6 2005 04:37:46:123PM1050506030Yijun Lindud
May 6 2005 04:53:06:623PM1050506031Yijun Linplasma to 0.23 sec
May 6 2005 05:10:29:187PM1050506032Yijun Linplasma to 1.7 sec. 700 kA. nl = 1.20. Similar to shot 25.
density did not rise. 1 MW RF in.
A very rare case that the last shot is the best shot in a run.

Physics Operator Comments
May 6 2005 09:01:23:457AM1050506001Steve Wolfe
Shot#1:
Earl is running a little late. 
I loaded the last shot from yesterday (with
title changed to "600kA limited, recovery shot".

Earl is back, he'll take over from shot 2.

May 6 2005 09:18:40:990AM1050506001Earl MarmarSteve loaded last shot from yesterday.

Plasma

Serious runaway shot. Current dipped, then rose. YAG claims central density gets to 8e20, but this is difficult to believe. ECE does appear cut-off.
May 6 2005 09:38:08:973AM1050506002Earl Marmarincrease prefill puff by 2 msec
decrease segment 1 PG3 puff

plasma

another bad runaway shot
YAG gets to 1e21 on axis
May 6 2005 09:58:05:080AM1050506003Earl Marmarprepuff to 25 msec
EF4 current 20 Amps less negative for t < 0

fizzle; got to about 40 kA, then went up
May 6 2005 10:08:34:067AM1050506004Earl MarmarB_r offset to -.0005 T from 0.00000

plasma
some runaways early, but much, much better
wall-fueled to death at .67 s

May 6 2005 10:22:47:893AM1050506005Earl Marmarno pcs changes
plasma
shorter
more hards
May 6 2005 10:31:28:503AM1050506006Earl Marmarreduce segment pg3 puff a bit
BR_0 to -.0007 from -.0005

plasma
better; lasted .9 s
still have uncontrolled fueling
May 6 2005 10:41:29:707AM1050506007Earl MarmarProgram I_p rise to 1 MA after .5 seconds

plasma
more runaways, slow current rise, dies at .3 seconds
May 6 2005 10:59:32:380AM1050506008Earl Marmarraise prepuff 2 msec to 26 msec

better; lasted to 1 second
still fueling from the walls
I_p got to about .75 MA, program was asking for 1 MA
May 6 2005 11:10:21:927AM1050506009Earl Marmarincrease EF4 at t < 0 by 10 A, to -1335A
reduce Ip ramp to 800 kA

strong fizzle
got to about 85 kA and then died
May 6 2005 11:32:06:473AM1050506010Earl Marmarcell access before this shot to reopen Thomson gate valves and to connect some DNB instrumentation

no pcs changes

plasma
lots of runaways
lasted about .4 seconds
pressure at breakdown continues to drop
May 6 2005 11:46:48:660AM1050506011Earl Marmarincrease prepuff another 2 msec to 28 msec

plasma
.24 seconds
mega-runaways
May 6 2005 12:06:32:423PM1050506012Earl MarmarEF4 another 10 amps less negative (now -1325)
increase prepuff 2 ms (to 30 msec)

plasma
better, hards but less intense
1 MW RF starting at .6 s, then density starts its rapid rise
RF is clearly doing some heating
May 6 2005 12:12:11:067PM1050506013Earl Marmarno pcs changes

mega runaway shot, like 1050506001
May 6 2005 12:29:18:857PM1050506014Earl Marmaradd 1 msec to prepuff, now 31 msec
plasma

nice startup; fast Ip rise, no hesitation.
goes seriously south starting at 0.1 seconds
May 6 2005 12:39:53:623PM1050506015Earl Marmaradjust Ip demand at 0.1 seconds to 500kA

plasma
similar to 14, but lasts a bit longer
May 6 2005 12:55:49:700PM1050506016Earl Marmarno pcs changes

plasma

similar to 14 and 15
May 6 2005 01:22:19:107PM1050506017Earl Marmarreduce Ip target to 700 kA

plasma

longest one yet (1.1 s)
still fueled to death at the end
May 6 2005 01:20:20:593PM1050506018Earl Marmarmove segment 1 RCUR in by 1 cm at 0.1 s

plasma

got to 200 kA and died
May 6 2005 01:35:38:670PM1050506019Earl Marmarmove RCUR out by 5 mm at 0.1 s

plasma past 1 sec; usual density rise to disruption
May 6 2005 01:43:41:187PM1050506020Earl Marmarmodify Ip program to stay a bit higher early
plasma
much shorter; slow Ip startup
May 6 2005 01:59:01:187PM1050506021Earl Marmaradd 1 msec to prepuff, now 32 msec

load segment 2 from 1050426022 into segment 3 (LSN fiducial-like)
turn off segment 2
turn on segment 3
reduce Ip to 700 kA

plasma
ok startup, goes bad after .1 s

May 6 2005 02:31:05:733PM1050506022Earl Marmarreduce nl_04 prog to 5e19

plasma
decent until about .7 s, then disrupt

May 6 2005 02:32:58:607PM1050506023Earl Marmarno pcs changes

plasma

shorter, but one of the better ones after a semi-long shot
disrupt at .36 s

lost pf breaker; power room access after the shot to check supplies
May 6 2005 03:03:30:890PM1050506024Earl Marmarno pcs changes
plasma
lasts .41 seconds, lots of hards

May 6 2005 03:15:34:530PM1050506025Earl Marmaradd 1 msec to prefill puff (now 33 ms)

good shot into rampdown
density is much higher than programmed, but fairly steady until about 1.4 s



May 6 2005 03:26:41:390PM1050506026Earl Marmarno pcs changes

dud - no TF

May 6 2005 03:43:58:390PM1050506027Earl Marmarno pcs changes

plasma
short
some hards
May 6 2005 04:12:36:843PM1050506028Earl Marmarno pcs changes

plasma
.45 seconds
data acquisition problems; missing data
May 6 2005 04:26:39:873PM1050506029Earl Marmarno pcs changes

power supply dud
OH1 did not behave around t=0

May 6 2005 04:35:32:250PM1050506030Earl Marmarno pcs changes

power supply dud
same OH1 problem

May 6 2005 05:10:38:593PM1050506031Earl Marmarno pcs changes

plasma
turns over early, ends at .23 s

May 6 2005 05:11:44:077PM1050506032Earl Marmarno pcs changes

plasma
made it into rampdown
very similar to shot 25
Density is still well above the target, but was constant during the flat-top.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:03:33:393AMPlasmaOk
209:27:41:740AMPlasmaOk
309:43:27:847AMPlasmaOk
409:57:41:113AMPlasmaOk
510:10:16:410AMPlasmaOk
610:22:44:380AMPlasmaOk
710:35:35:957AMPlasmaOk
810:48:03:723AMPlasmaOk
911:06:22:567AMPlasmaOk
1011:23:52:847AMPlasmaOk
1111:36:39:707AMPlasmaOk
1211:52:53:880AMPlasmaOk
1312:06:08:177PMPlasmaOk
1412:18:42:750PMPlasmaOk
1512:31:12:013PMPlasmaOk
1612:44:04:107PMPlasmaOk
1712:56:35:107PMPlasmaOk
1801:11:12:093PMPlasmaOk
1901:24:14:450PMPlasmaOk
2001:36:54:873PMPlasmaOk
2101:51:36:717PMPlasmaOk
2202:04:13:827PMPlasmaOk
2302:19:32:967PMPlasmaOk
2402:53:48:230PMPlasmaOk
2503:06:39:107PMPlasmaOk
2603:20:11:547PMPlasmaBadNo TF
2703:33:15:547PMPlasmaOk
2803:47:59:857PMTestBad
2904:15:21:187PMPlasmaOk
3004:31:25:170PMPlasmaBadOH 1 charging switch did not close
3104:50:08:670PMPlasmaOk
3205:05:05:420PMPlasmaOk