Alcator C-Mod Run 1031016 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader: Unknown (shots 1-34)

Operators
Session leader(s): Unknown
Physics operator(s):Earl Marmar
Engineering operator(s): Unknown

Engineering Operator Run Comment
Purpose: Plasma Startup and Conditioning.

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:37:19:350PM
Author: Earl Marmar
1031016 physop run summary

continuing machine cleanup, rf conditioning and diagnostic checkout

Start with lower single null. Possibly move to upper null later.

Keep an eye on H/(H+D).

PO Marmar
___________________________________________________________

ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00.
Bake at 60 C overnight as well.

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

Power systems the same as on 1031015023 (0.8 MA, lower null)

Gas setup:
fill B-Top with 6 psi 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) (for ECDC)
fill C-side with 30 psi D2 Hybrid enabled (PG3)

Enable the following gate valves: ECE, VUV, DNB

-----------------------------------------------------------------------
RF Setup: Transmitters 1,2 in RUN ON by 08:00 am

-----------------------------------------------------------------------
Run Plan: Continue running cleanup plasmas while monitoring H/D, etc.

RF Group will continue conditioning D & E.


Summary:

The run went reasonably well, but there were a lot of fizzles and
duds. All plasma shots were lower single null. We tried 10 minutes of
ECDC once between shots (before shot 21) and then got 3 plasmas in a
row. Changes were mostly made to prefill pressure and EF4 at t=0. The
RF ran D and E, getting ~1 MW into plasma from each, with up to 2 MW
total when both were on at the same time.H/D started low on the first
shot (~5%) and quickly rose to around 15% with RF power. It stayed
roughly constant after that, falling a bit after the between shot
ECDC.

Scorecard:
plasmas 18
fizzles 10
duds 6

total cycles 34

Session Leader Comments

Physics Operator Comments
Oct 16 2003 08:51:45:970AMEarl Marmarcontinuing machine cleanup, rf conditioning and diagnostic checkout

Start with lower single null. Possibly move to upper null later.

Keep an eye on H/(H+D).
Oct 16 2003 09:06:00:473AM1031016001Earl Marmarload from 1031015002
load segment 2 from 1031015023 (lower single null, 800 kA) into model segment 2

plasma

Disrupt at 0.48 s; breaker tripped on OH1, but plasma was heading south before that.

Oct 16 2003 09:19:48:747AM1031016002Earl Marmarreduce prepuff by 2 msec; nl_04 to 0.8e20 from 1e20

plasma; full length
Oct 16 2003 09:38:35:247AM1031016003Earl Marmarno pcs changes

plasma

H/(H+D) = .12
Oct 16 2003 09:57:33:543AM1031016004Earl Marmarno pcs changes

plasma;; H/(H+D) = .12 to .14
Oct 16 2003 10:08:17:240AM1031016005Earl Marmarreduce clearin 5 mm rcur 2.5 mm (Bruce requested smaller inner gap for impurity measurements)

plasma; got reduced inner gap; early marfe seems to be getting intense

H/(H+D) = .16
Oct 16 2003 10:21:34:700AM1031016006Earl Marmarslow early current rise; raise Ip to .9 MA; nl_04 up to 1e20

plasma; early marfe much better; H/(H+D) ~ .15
Oct 16 2003 10:43:32:807AM1031016007Earl Marmarno pcs changes

plasma; disrupt near end of flat-top, EF1U hit limit; lost the inner gap
density increase at 0.5 seconds (dithering?)

H/(H+D) = .14 to .16; .24 during disruption
Oct 16 2003 10:45:49:273AM1031016008Earl Marmarreduce Ip 50 kA, reduce nl_04 to 9e19, decrease prepuff by 1 msec

fizzle


Oct 16 2003 11:05:41:133AM1031016009Earl Marmarreduce prepuff by 2 msec to 19 msec

fizzle
Oct 16 2003 11:18:05:920AM1031016010Earl Marmarno pcs changes

plasma; funny density rise/dithering is gone

H/(H+D) = .14 to .19
Oct 16 2003 11:31:17:863AM1031016011Earl Marmarno pcs changes

fizzle
Oct 16 2003 11:39:58:747AM1031016012Earl Marmarreduce BR_0 offset by .3 mT to 0.0002

dud
Oct 16 2003 11:52:10:003AM1031016013Earl Marmaradd 2 msec to prepuff

dud
Oct 16 2003 12:06:02:727PM1031016014Earl Marmaradd 0.5 mT to BR_0 offset (now .0007 T)

dud
Oct 16 2003 12:31:31:350PM1031016015Earl MarmarEF4 20 amp more negative (now -1330)

BR_0 offset back to 0.0005

plasma

H/(H+D) = .11 to .18
Oct 16 2003 12:43:28:807PM1031016016Earl Marmarno pcs changes

plasma

H/(H+D) = .11 to .18
Oct 16 2003 12:47:40:150PM1031016017Earl Marmarno pcs changes

fizzle
Oct 16 2003 01:06:15:493PM1031016018Earl Marmarreduce prepuff by 1 msec

fizzle
Oct 16 2003 01:21:53:607PM1031016019Earl Marmartake another 10 A off EF4

plasma

early marfe is back

H/(H+D) = .13 to .19
Oct 16 2003 01:32:49:567PM1031016020Earl Marmarno pcs changes

fizzle

discharge clean for 10 minutes before shot 21
Oct 16 2003 02:01:41:340PM1031016021Earl MarmarECDC for 10 minutes before this shot.

Reduce prepuff by 1 msec

add 10 msec to argon puff

plasma

H/(H+d) = .1 to .16
Oct 16 2003 02:13:57:753PM1031016022Earl Marmarno pcs changes

plasma

H/(H+D) = .1 to .15
Oct 16 2003 02:34:26:457PM1031016023Earl Marmarno pcs changes

plasma

H/(H+D) = .1 to .16
Oct 16 2003 02:37:17:330PM1031016024Earl Marmarno pcs changes

fizzle
Oct 16 2003 02:54:43:723PM1031016025Earl Marmarreduce prefill 1 msec (to 18 msec)

plasma

bouncy startup, with runaways

H/(H+D) = .1 to .16
Oct 16 2003 03:08:28:307PM1031016026Earl Marmaradd 1 msec to prepuff

plasma

no bounce, no hards

H/(H+D) = .09 to .15
Oct 16 2003 03:20:18:407PM1031016027Earl Marmarno pcs changes

fizzle
Oct 16 2003 03:32:16:973PM1031016028Earl Marmarreduce prepuff by 1 msec to 18 msec

reduce I_p by 50 kA

tweak current rise after 0.1 seconds

dud
Oct 16 2003 03:50:09:867PM1031016029Earl Marmaradd 2 msec to prepuff

take 20 A off EF4 (now -1360)

plasma

H/(H+D) = .09 to .15
Oct 16 2003 03:57:08:220PM1031016030Earl Marmarno pcs changes

fizzle
Oct 16 2003 04:12:58:063PM1031016031Earl Marmarreduce prepuff 2 msec

dud
Oct 16 2003 04:24:03:803PM1031016032Earl Marmaradd 2 msec to prepuff

dud
Oct 16 2003 04:43:57:820PM1031016033Earl Marmaradd 20 amps back to EF4, now -1340 A

plasma

H/(H+D) = .09 to .15
Oct 16 2003 04:56:06:297PM1031016034Earl Marmarno pcs changes

fizzle

end of run

Engineering Operator Comments
ShotTimeTypeStatusComment
108:55:36:827AMPlasmaBadOH1 self powered circuit fired
209:13:07:750AMPlasmaOk
309:27:02:927AMPlasmaOk
409:44:30:773AMPlasmaOk
509:58:05:857AMPlasmaOk
610:13:30:610AMPlasmaOk
710:27:07:147AMPlasmaOk
810:42:33:887AMPlasmaOk
910:56:59:530AMPlasmaOk
1011:10:03:973AMPlasmaOk
1111:23:06:730AMPlasmaOk
1211:36:04:733AMPlasmaOk
1311:49:13:037AMPlasmaOk
1412:02:40:027PMPlasmaOk
1512:16:03:580PMPlasmaOk
1612:29:14:380PMPlasmaOk
1712:42:24:887PMPlasmaOk
1812:58:23:750PMPlasmaOk
1901:11:43:787PMPlasmaOk
2001:26:31:993PMPlasmaOk
2101:51:56:350PMPlasmaOk
2202:05:40:197PMPlasmaOk
2302:18:53:703PMPlasmaOk
2402:33:02:050PMPlasmaOk
2502:45:59:387PMPlasmaOk
2602:59:17:813PMPlasmaOk
2703:14:21:143PMPlasmaOk
2803:27:31:603PMPlasmaOk
2903:40:46:517PMPlasmaOk
3003:53:48:647PMPlasmaOk
3104:07:53:147PMPlasmaOk
3204:21:01:307PMPlasmaOk
3304:34:14:000PMPlasmaOk
3404:52:00:847PMPlasmaOk