Alcator C-Mod Run 1010717 Information

Back to runs

Miniproposals
Miniproposal:289a
Date Filed: 5/2/2001
Title:Investigations of Double Transport Barrier Plasmas
First Author:John Rice
Session Leader:John Rice (shots 1-21)

Operators
Session leader(s):John Rice
Physics operator(s):Earl Marmar
Engineering operator(s):Bill Byford,Gary Dekow

Engineering Operator Run Comment
SL:Rice PO:Marmar EO:Byford/Dekow MP289A Double Barrier

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:27:180PM
Author: To Be Determined
Session Leader Run Summary for 1010717 MP289A Double Barrier Studies

Several double barrier plasmas were formed at 4.5 T using D and E port
(4, 6, 7, 10, 16), however J-port only operated above 500 kW on one discharge
(17), which was the only plasma with an arrested ITB. This particular plasma
also had a TF reramp, so it is ambiguous as to which arrested the barrier.
As such, not much headway was made into MP289A except that the barrier
could be formed fairly reliably early in the run, before H/D rose above
10%. The run began with several duds, presumably due to J-port conditioning.
There was also a string of 3 unexplained duds in the middle of the run.
The later shots were plagued by H-L transitions which destroyed the ITB,
because of the high H/D ratio.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:13:863PM
Author: To Be Determined
Run Plan and ENGINEERING SETUP FOR Tuesday 1010717

MP289A Double Barrier
SL: Rice
PO: Marmar

ECDC in D2 overnight, stopping by 8:00 am

RUN BEGINS AT 9:00 am AND ENDS AT 5:00 pm

Power systems the same as for shot 1010716016

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)
fill J-Bottom with 30 psi He Hybrid DISABLED(PG5)
Enable the following gate valves, assuming no vacuum problems:
ECE, DNB, VUV

RF STATUS:

XMTR 1 AND 2, RUN-ON STARTED AT 8:00 AM
XMTR 3 AND 4, RUN-ON STARTED AT 8:00 AM

RUN PLAN:

Pick up where we left off on Monday. Try to optimize the off-axis core barrier
plasma and then add on-axis heating.

Piggybacking by MP281 Edge Turbulence Imaging is expected.


Results:

The run started with 3 duds (J-port was vacuumed conditioned just before shot
1). After 3 rounds of ECDC, we got a good plasma on shot 4, with a good core
barrier. J-port proved difficult to couple reliably, so eventually we went to
D+E only, with TF ramps to investigate formation of the core barrier, followed
by TF increases to try to arrest the core buildup. See the session leader
summary for details.

There were several fizzles, and in addition to the duds at the beginning of the
day, we had 2 more duds in the middle of the run (shots 12 and 13). The fields
and gas all looked pretty good. We had more ECDC, and tweaked the fields a bit,
after which there were no more duds for the remainder of the run.

H/D was rising on every shot during RF, typically to 0.1 or a little higher.
ECDC in D_2 was run before most shots. See the logbook for details.

Scorecard:

Plasmas 13
Fizzles 3
Duds 5
Tests/no power 0

Total cycles 21



Session Leader Comments
Jul 17 2001 09:24:32:597AM1010717001John Ricecanonical post-J-port conditioning dud
Jul 17 2001 09:48:29:377AM1010717002John Ricenon-canonical post-J-port conditioning dud
Jul 17 2001 10:28:02:580AM1010717003John Rice2nd non-canonical post-J-port conditioning dud
Jul 17 2001 10:47:32:617AM1010717004John Ricegreat ITB formation
Jul 17 2001 11:01:37:767AM1010717005John Ricefiz
Jul 17 2001 11:25:15:750AM1010717006John Riceanother excellent ITB
no J-port
Jul 17 2001 11:56:24:810AM1010717007John Riceanother excellent ITB
no J-port
Jul 17 2001 12:20:02:357PM1010717008John Ricelost ITB at 0.9s
no J-port
Jul 17 2001 12:27:52:573PM1010717009John Ricefiz
Jul 17 2001 12:56:50:600PM1010717010John Riceexcellent ITB
300 kW from J-port
Jul 17 2001 01:18:16:233PM1010717011John Ricetransient ITB
no J-port
Jul 17 2001 01:18:34:390PM1010717012John Ricedudly
Jul 17 2001 01:36:26:627PM1010717013John Ricedudly
Jul 17 2001 02:13:53:933PM1010717014John Ricedudly
Jul 17 2001 02:19:13:663PM1010717015John RiceITB
D-port trip
Jul 17 2001 02:44:11:460PM1010717016John Riceexcellent ITB
no J-port
Jul 17 2001 03:07:29:647PM1010717017John Riceexcellent ITB, rotation returned w/ TF reramp and/or
600 kW J-port
Jul 17 2001 03:26:45:557PM1010717018John RiceITB, rotation returned w/ TF reramp but went out of H-mode
0 kW J-port
Jul 17 2001 04:10:23:533PM1010717019John RiceITB, rotation returned w/ TF reramp but went out of H-mode
0 kW J-port
Jul 17 2001 04:38:37:697PM1010717020John RiceITB, rotation returned w/ TF reramp but went out of H-mode
0 kW J-port
Jul 17 2001 04:55:28:133PM1010717021John RiceITB but went out of H-mode
0 kW J-port

Physics Operator Comments
Jul 17 2001 08:57:31:670AMEarl Marmar
Run Plan and ENGINEERING SETUP FOR Tuesday 1010717

MP289A Double Barrier
SL: Rice
PO: Marmar

ECDC in D2 overnight, stopping by 8:00 am

RUN BEGINS AT 9:00 am AND ENDS AT 5:00 pm

Power systems the same as for shot 1010716016

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)
fill J-Bottom with 30 psi He Hybrid DISABLED(PG5)
Enable the following gate valves, assuming no vacuum problems:
ECE, DNB, VUV

RF STATUS:

XMTR 1 AND 2, RUN-ON STARTED AT 8:00 AM
XMTR 3 AND 4, RUN-ON STARTED AT 8:00 AM

RUN PLAN:

Pick up where we left off on Monday. Try to optimize the off-axis core barrier
plasma and then add on-axis heating.

Piggybacking by MP281 Edge Turbulence Imaging is expected.
Jul 17 2001 08:57:58:060AMEarl Marmarcoldstart

all matrices respond

no errors
Jul 17 2001 09:01:52:193AM1010717001Earl Marmarload from 1010716016

load segment 1 from 1010716007

J-port was conditioning just before the run

lower prepuff to 19 msec
Jul 17 2001 09:21:10:217AM1010717001Earl Marmardud
Jul 17 2001 09:53:06:200AM1010717002Earl MarmarECDC in D_2 for 15 minutes before shot (P_fill = 4e-4)

increase prepuff to 22 msec

dud
Jul 17 2001 10:22:04:427AM1010717003Earl MarmarECDC in D_2 for 15 minutes before shot (P_fill = 4e-4)

take 15 amps off EF4 (now -1285)

reduce BR_0 offset by .55 mT

dud
Jul 17 2001 10:53:13:330AM1010717004Earl Marmarno ECDC before shot

raise BR_0 offset 0.4 mT

plasma

nice core peaking (central density to 8e20)
Jul 17 2001 11:04:52:790AM1010717005Earl MarmarECDC before shot (H/D was rising strongly on Shot 4)

no PCS changes

fizzle
Jul 17 2001 11:43:00:660AM1010717006Earl Marmarno ECDC before shot

add .4 mT to BR_0 offset

remove 1 msec from prepuff

plasma
Jul 17 2001 12:09:07:507PM1010717007Earl MarmarECDC 6 minutes before shot

no PCS changes

plasma
Jul 17 2001 12:09:37:133PM1010717008Earl MarmarECDC 5 minutes before shot

no PCS changes

plasma

Jul 17 2001 12:32:59:800PM1010717009Earl MarmarECDC 7 minutes before shot

no PCS changes

fizzle
Jul 17 2001 12:55:46:940PM1010717010Earl Marmarno ECDC before shot

reduce BR_0 offset by 0.5 mT

plasma
Jul 17 2001 01:13:51:177PM1010717011Earl MarmarECDC in D_2 for 7 minutes before shot

reduce prepuff by 1 msec

plasma
Jul 17 2001 01:22:42:240PM1010717012Earl Marmarno ECDC before shot

no PCS changes

dud; fields & gas look fine
Jul 17 2001 01:46:46:303PM1010717013Earl Marmarno ECDC before shot

dud


Jul 17 2001 02:03:23:040PM1010717014Earl MarmarECDC for 11 minutes before shot

increase BR_0 offset by 0.5 mT

fizzle; late breakdown; B_z looks too high; fill also a tad high
Jul 17 2001 02:21:45:683PM1010717015Earl Marmarno ECDC before shot

EF4 15 A more negative before t=0

plasma
Jul 17 2001 02:35:32:693PM1010717016Earl MarmarECDC for 10 minutes before shot (P_fill = 2e-4)

no PCS changes

plasma


Jul 17 2001 03:07:31:240PM1010717017Earl MarmarECDC 10 minutes before shot

change TF waveform to ramp back up to 5.3 T, starting at 0.85 s

plasma
Jul 17 2001 03:36:00:670PM1010717018Earl MarmarECDC for 7 minutes before shot

reduce TF re-ramp, going up to 130 kA starting at 0.85 seconds

plasma
Jul 17 2001 04:15:53:967PM1010717019Earl MarmarECDC 8 minutes before shot

DNB will fire at 0.7 to 0.8 s

reduce prepuff by 2 msec

plasma
Jul 17 2001 04:34:32:283PM1010717020Earl MarmarECDC for 9 minutes before shot

add 1 msec to prepuff (now 21 msec)

plasma

Engineering Operator Comments
ShotTimeTypeStatusComment
109:16:24:567AMPlasmaOk
209:46:25:937AMPlasmaOk
310:15:40:180AMPlasmaOk
410:34:35:123AMPlasmaOk
510:56:09:367AMPlasmaOk
611:16:45:470AMPlasmaOk
711:38:33:777AMPlasmaOk
812:04:55:483PMPlasmaOk
912:26:11:257PMPlasmaOk
1012:38:44:470PMPlasmaOk
1112:59:32:883PMPlasmaOk
1201:15:54:900PMPlasmaOk
1301:29:30:660PMPlasmaOk
1401:54:47:757PMPlasmaOk
1502:10:53:570PMPlasmaOk
1602:33:41:737PMPlasmaOk
1702:55:25:480PMPlasmaOk
1803:16:07:617PMPlasmaOk
1904:05:17:240PMPlasmaOk
2004:29:51:570PMPlasmaOk
2104:51:27:563PMPlasmaOk