Alcator C-Mod Run 931001 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Earl Marmar (shots 1-25)
Session Leader:Earl Marmar (shots 1-25)

Operators
Session leader(s):Earl Marmar,Earl Marmar
Physics operator(s):Earl Marmar
Engineering operator(s):Frank Silva

Engineering Operator Run Comment
silva, in the con

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:09:023PM
Author: To Be Determined

From: ZENITH::MARMAR
Date: 4-OCT-1993 22:36:14
Description: Session leader summary 931001

931001 Between shot ECDC; D2 plasma working gas.

The main purpose of the run was to investigate the effects of between-shot
ECDC, particularly with regard to post disruption cleanup. Developing
higher elongation and measuring growth rates of vertical instabilities
were piggy-back goals.

We mostly did the ECDC in He, with the exception of between shots 11 and
12, where it was done in D_2. All ECDC was performed with fill pressure of
5e-4 Torr (gauge). In general, after each fast VDE (induced by
turning off EFC feedback at high kappa), we had at least one fizzle. The
exceptions were shot 11 (no ECDC before), and shot 14 (preceeded by 10 minutes
of He ECDC). While there are too few shots to allow for definite
conclusions, it does not appear that the ECDC after a disruption prevented
a subsequent fizzle. In fact, it appeared that the ECDC may have made
things slightly worse. In particular, shot 11 went after the 600 kA VDE on
shot 10 (although 11 was not pretty during the breakdown and current rise
phase). Measurements of low Z impurity light, as well as H-alpha and He
Lyman-alpha, were made, but no obvious conclusions have yet emerged. It is
a fact that the RGA spectrum on Monday was about as clean as it has ever
been (there was also a 60 degree mini-bake on Saturday).

My shot by shot summary follows.

1 power supply problems dud
2 attempt again; late breakdown fizzle
3 OH2l did not reverse. 600 kA, then ramping down at .4s plasma
VDE down at .64s, 300kA.
4 600 kA, no disruption, Z~1.5, 380 kW rad power plasma
5 600 kA, VDE plasma
attempted to ECDC in He, but it tripped after about 2 seconds
6 still having some OH2l problems, but this is not the fizzle
cause of the fizzle.
After 6, we ECDC'd for 10.0 minutes in helium.
7 slightly better breakdown fizzle
after 7, ECDC'd in He for 10.4 minutes
8 EF2 lower problem. dud
no ECDC after shot 8.
9 very similar to 7, slightly better breakdown fizzle
no ECDC after shot 9
10 600 kA, VDE up at .76 s, Mo injection at .66 s. plasma
no ECDC after shot 10
11 600 kA, VDE up at .74 s, high kappa plasma
10.0 minutes ECDC in D2 after shot 11
12 fizzle fizzle
10 minutes ECDC in He after shot 12
13 600 kA, VDE up at .71 s, Mo injections throughout plasma
10 minutes ECDC in He after shot 13
14 200 kA, disrupt at .16 s. plasma
no ECDC after shot 14
15 600 kA, VDE up =at .76 plasma
ECDC for 10 minutes in He after shot 15
16 late breakdown, B_R uptick? fizzle
ECDC for 7 minutes in He after shot 16
17 very late breakdown, another B_R spike fizzle
ECDC for 7 minutes in He after shot 17
18 breakdown at normal time fizzle
no ECDC after shot 18
19 600 kA, VDE up at .77 s plasma
no ECDC after shot 19
20 breakdown at normal time fizzle
21 delay pulsed gas 2 msec; pellet attempt at .5 s; disrupt at plasma
.54 s, following pellet; 540 kA VDE;
no ECDC after shot 21.
22 fizzle fizzle
no ECDC after shot 22
23 lower fill to 1.0e-5 (it had been 1.1e-5 up to now all day) plasma
high density (>1e20), disrupt at .42 s, 413 kA
5 minutes ECDC in He after shot 23
24 lower fill to 9.0e-6; bounced on outer limiter early fizzle
no ECDC after 24
25 some field tweaks (lowered B_R) dud

11 plasma, 11 fizzles, 2 power supply duds, 1 other dud.

Physics Operator Summaries

Session Leader Comments
Oct 1 1993 09:06:32:600AMEarl MarmarToday's run:

Mini-poroposal 31, between shot ECDC. Piggy back is MP24, High kappa.

Start from 930930005 with some tweaks.

Oct 1 1993 09:44:32:860AM931001002Earl MarmarFizzle; late breakdown.

Physics Operator Comments

Engineering Operator Comments
ShotTimeTypeStatusComment
109:06:51:960AMPlasmaBadmultiple ps problems
209:27:53:450AMPlasmaBadoh2 comm fail
309:47:25:910AMPlasmaBadoh2 fault
410:02:19:060AMPlasmaOkno faults plasma
510:17:09:300AMPlasmaOkPower supplies O.K.
610:38:47:700AMPlasmaOkNo faults Fizzle
711:03:24:140AMPlasmaOkecdc between shot 6&7
811:28:13:830AMPlasmaBadef2 unscheduled output faulse
911:46:44:950AMPlasmaOkwater leak fe2 la
1012:21:43:460PMPlasmaBadplasma ps ok
1112:36:38:330PMPlasmaOkplasma
1201:01:45:610PMPlasmaOkecdc bd
1301:28:42:250PMPlasmaOkok
1401:49:28:900PMPlasmaOkNo faults
1502:04:17:040PMPlasmaOkok ecdc between shot
1602:26:40:540PMPlasmaOkecdcplasma
1702:45:32:420PMPlasmaOkecdc between shots
1803:06:01:590PMPlasmaOkecdc between shots
1903:20:48:520PMPlasmaOkoh2 lower fault
2003:45:37:710PMPlasmaOkNo faults fizzle
2103:58:50:550PMPlasmaOkplasma
2204:16:22:280PMPlasmaOkfiz
2304:31:10:170PMPlasmaBadComm Fail OH2U&L, EF1 OH1
2404:48:05:550PMPlasmaOkplasma
2505:02:38:600PMPlasmaOklast shot dud