Alcator C-Mod Run 1040310 Information

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Miniproposals
Miniproposal:373
Date Filed:11/25/2003
Title:ITB Current Scan Revisted
First Author:Catherine Fiore
Session Leader:Catherine Fiore (shots 1-27)

Operators
Session leader(s):Catherine Fiore
Physics operator(s):Earl Marmar
Engineering operator(s):Bill Parkin,Ed Fitzgerald,Gary Dekow

Engineering Operator Run Comment
MP#373 Ip current scan at 6.3T; Sl:Fiore; PO:Marmar; EO:Dekow/Fitz/Parki

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:03:477PM
Author: Catherine Fiore


This run is in support of MP 371: ITB Current Scan Revisited.

S.L. Fiore
P.O. Marmar

Since the 70 Mhz system is not available, we will be doing this scan at high
field (6.43 T) and using the 80 Mhz off-axis on the low field side to make
ITBs. The purpose is explore the ITB foot position as a function
of field/current/q by doing a current scan at a different magnetic field
(we have an earlier current scan at 4.5 T.)

We will start with ITB development from 1040309031 and raise the magneticfield.

We will try to get ITBs on 2-3 shots per current setting.

---------

This run was pretty successful,wit ITBs achieved at 6.43 T with currents of
0.85,1.1,1.2 and 1.3 MA. The foot location clearly widened with increasing
plasma currents. We didn't have as many good shots as yesterday, but certainly
enough to declare the run a success.

The best ITBS were on shots 10,12,13,14,15,23,25.
Shots 16, 18, and 22 had less impressive ITBs due to back transitions.

Shot summary:

1040310001 There are some problems with data collection on this shot, but it
seems unlikely that there was an ITB. The toroidal field was slightly too
high. There was a nice H-mode, however.

1040310002 There was a nice H-mode but no ITB however. The toroidal field
was correct this time.There were quite a few trips on the rf power We will
try to even those out on the next shot.

1040310003 There was a nice H-mode but no ITB however. The last 3 shots were at
0.8 ka. We are going to see if we can get it at 1 MA.

1040310004 No TF

1040310005 Nice steady H-mode with steady rf but still not ITB. There was
an unexplained improvement in confinement at about 1.3 s. We will try
going up on the rf power.

1040310006 Nice steady H-mode with steady rf but still not ITB. There was
an unexplained improvement in confinement at about 1.3 s. We will try
lowering the target density.

1040310007 Nice steady H-mode with steady rf but still not ITB. There was
an unexplained improvement in confinement at about 1.3 s. There are
data system problems.

1040310008 This shot was aborted. The data system was messed up.

1040310009 H-mode ending in a hard disruption. Data system is messing
up.

1040310010 H-mode, ITB finally! Lowering the lower trangularity
a little bit helped. We will scan the current up, trying for 1.1 MA

1040310011 H-mode but with 2 back transitions. Some peaking, but not a strong
sustained ITB. We will try to raise the density a little.

1040310012 H-mode with a nice ITB. We will try to raise the power by 0.2 MW.

1040310013 H-mode with nice ITB but late back transition. We will move to a
lower current point. The density and rf power are both also being lowered
slightly.

1040310014 H-mode with nice ITB. The GPC gate valve did not open for that
shot so we are going to take a repeat.

1040310015 H-mode with nice ITB, although it starts late. We will try to
raise the rf power and see if we can launch the ITB earlier.

1040310016 H-mode with some ITB but late back transition. We are going up
in current to 1.3 MW and lowering the field to 6.35 T. The target density
and rf power should also increase.

1040310017 H-mode with lots of back transitions. The rf tripped out early
then the data system tripped out, so the data set is incomplete.

1040310018 H-mode, with ITB.

1040310019 H-mode. Too many back transitions for ITB. We will back off to
1.2 MA and return the field to 6.43 T.

1040310020 Fizzle

1040310021 H-mode, starting to peak up but then a number of back transitions
halted the ITB formation. We will try to adjust the rf power and the target
density.

1040310022 H-mode, starts into an ITB then goes into a fatal back
transition at t=1.1.


1040310023 H-mode, Very nice ITB.We will try to increase the density a little
more.

1040310024 fizzle

1040310025 H-mode, ITB, but back transitions early. Not as nice as 23. We
are going to lower the field to 5.4 and try to get a comparison
shot for confinement purposes.

1040310026 H-mode with many back transitions and rf trips. The stored energy
started at a was similar value to the previous shot, however.

1040310027 fizzle

Physics Operator Summaries
Entered: Jul 7 2004 04:36:49:473PM
Author: Earl Marmar
Physop summary 1040310

MP#373 Ip current scan to be done at 6.3T.

SL: Fiore
PO: Marmar



ECDC overnight ECDC overnight (2e-4 torr deuterium)

Run begins at 09:00, ends at 17:00

Power supplies as on 1021018018

Gas System Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
leave B-side upper with 15 psi He3 Hybrid DISABLED (PG2)
fill C-side with 30 psi D2 Hybrid enabled (PG3)
fill NINJA (lower cap) with 8 psi D2

Gate valve permissives for the usual suspects (ECE, VUV, DNB) assuming no vacuum problems

RF: Transmitters #1and 2in RUN-ON by 08:00

A-coils off, at least to start

Plan:
Current scan with 80 MHz ITB's at 6.3 tesla

________________________
Results:

It took some fiddling to get good ITB's. The first was on shot 10,
after increasing RXL by 1 cm. Things improved further on shot 12, by
increasing the target nl_04 to 1.1e20 for this 1.1 MA shot.

Got most of the I_p scan done, including ITB's at 1.3 MA, with stored
energy exceeding 170kJ (e.g. shot 18) using only off-axis heating. We
did not turn on the A-coils.

There were some computer problems, and 1 no power shot due to a hang
in init. There was 1 no TF shot.

Scorecard:
plasmas 22
fizzles 3
P.S. Dud 1
No power 1

total 27 cycles

Session Leader Comments
Mar 10 2004 08:40:28:730AMCatherine FioreThis run is in support of MP 371: ITB Current Scan Revisited.

Since the 70 Mhz system is not available, we will be doing this scan at high field (6.43 T) and using the
80 Mhz off-axis on the low field side to make ITBs. The purpose is explore the ITB foot position as a function
of field/current/q by doing a current scan at a different magnetic field (we have an earlier current scan at
4.5 T.)

We will start with ITB development from 1040309031 and raise the magnetic field.

We will try to get ITBs on 2-3 shots per current setting.
Mar 10 2004 09:22:01:353AM1040310001Catherine FioreThere are some problems with data collection on this shot, but it seems unlikely that there was an ITB.
The toroidal field was slightly too high. There was a nice H-mode, however.
Mar 10 2004 09:36:57:063AM1040310002Catherine FioreThere was a nice H-mode but no ITB however. The toroidal field was correct this time.
There were quite a few trips on the rf power. We will try to even those out on
the next shot.
Mar 10 2004 09:51:02:007AM1040310003Catherine FioreThere was a nice H-mode but no ITB however. The last 3 shots were at
0.8 ka. We are going to see if we can get it at 1 MA.
Mar 10 2004 10:01:15:790AM1040310004Catherine FioreNo TF
Mar 10 2004 10:22:06:320AM1040310005Catherine FioreNice steady H-mode with steady rf but still not ITB. There was an unexplained improvement in confinement at
about 1.3 s. We will try going up on the rf power.
Mar 10 2004 10:33:19:353AM1040310006Catherine FioreNice steady H-mode with steady rf but still not ITB. There was
an unexplained improvement in confinement at about 1.3 s. We will try
lowering the target density.
Mar 10 2004 11:02:18:260AM1040310007Catherine FioreNice steady H-mode with steady rf but still not ITB. There was
an unexplained improvement in confinement at about 1.3 s. There are
data system problems.
Mar 10 2004 11:14:53:997AM1040310008Catherine FioreThis shot was aborted. The data system was messed up.
Mar 10 2004 11:24:37:560AM1040310009Catherine FioreH-mode ending in a hard disruption. Data system is messing
up.
Mar 10 2004 11:58:49:050AM1040310010Catherine FioreH-mode, ITB finally! Lowering the lower trangularity
a little bit helped. We will scan the current up, trying for 1.1 MA
Mar 10 2004 12:10:57:490PM1040310011Catherine FioreH-mode but with 2 back transitions. Some peaking, but not a strong sustained ITB. We will try to
raise the density a litttle.
Mar 10 2004 12:51:45:553PM1040310012Catherine FioreH-mode with a nice ITB. We will try to raise the power by 0.2 MW.
Mar 10 2004 12:45:02:307PM1040310013Catherine FioreH-mode with nice ITB but late back transition. We will move to a lower current point.
The density and rf power are both also being lowered slightly.
Mar 10 2004 01:08:05:420PM1040310014Catherine FioreH-mode with nice ITB. The GPC gate valve did not open for that shot so
we are going to take a repeat.
Mar 10 2004 01:18:06:467PM1040310015Catherine FioreH-mode with nice ITB, although it starts late. We will try to raise the rf power and see if we can launch
the ITB earlier.
Mar 10 2004 01:43:04:630PM1040310016Catherine FioreH-mode with some ITB but late back transition. We are going up in current to 1.3 MW and lowering the field
to 6.35 T. The target density and rf power should also increase.
Mar 10 2004 02:03:59:397PM1040310017Catherine FioreH-mode with lots of back transitions. The rf tripped out early then the data
system tripped out, so the data set is incomplete.
Mar 10 2004 02:41:39:360PM1040310018Catherine FioreH-mode, with ITB.
Mar 10 2004 03:08:57:513PM1040310019Catherine FioreH-mode. Too many back transitions for ITB.
Mar 10 2004 03:08:01:167PM1040310020Catherine FioreFizzle
Mar 10 2004 03:26:31:507PM1040310021Catherine FioreH-mode, starting to peak up but then a number of back transitions halted the ITB formation.
We will try to adjust the rf power and the target density.
Mar 10 2004 03:52:59:690PM1040310022Catherine FioreH-mode, starts into an ITB then goes into a fatal back transition at t=1.1.
Mar 10 2004 04:22:55:393PM1040310023Catherine FioreH-mode, Very nice ITB.
Mar 10 2004 04:44:38:757PM1040310025Catherine FioreH-mode, ITB, but back transitions early. Not as nice as 23. We
are going to lower the field to 5.4 and try to get a comparison
shot for confinement purposes.
Mar 10 2004 04:59:11:090PM1040310026Catherine FioreH-mode with many back transitions and rf trips. The stored energy started at
a was similar value to the previous shot, however.
Mar 10 2004 05:01:13:047PM1040310027Catherine Fiorefizzle

Physics Operator Comments
Mar 10 2004 08:54:51:920AMEarl MarmarMP#373 Ip current scan to be done at 6.3T.

____________________

ECDC overnight ECDC overnight (2e-4 torr deuterium)

Run begins at 09:00, ends at 17:00

Power supplies as on 1021018018

Gas System Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
leave B-side upper with 15 psi He3 Hybrid DISABLED (PG2)
fill C-side with 30 psi D2 Hybrid enabled (PG3)
fill NINJA (lower cap) with 8 psi D2

Gate valve permissives for the usual suspects (ECE, VUV, DNB) assuming no vacuum problems

RF: Transmitters #1and 2in RUN-ON by 08:00

A-coils off, at least to start

Plan:
Current scan with 80 MHz ITB's at 6.3 tesla
Mar 10 2004 09:22:46:917AM1040310001Earl Marmarstart from 1040309031
adjust TF to -180kA at flattop

plasma

many data acquisition errors (magnetics, etc.)
most (all?) recovered after the shot

2.4 MW RF, some trips
H-Mode, but no ITB

Mar 10 2004 09:29:03:867AM1040310002Earl MarmarTF flattop to -177.2 kA (from -180.) to get 6.43T

plasma

RF still many trips
H-Mode, no ITB


Mar 10 2004 10:01:17:290AM1040310003Earl Marmarno pcs changes

plasma
H-mode, no ITB

Mar 10 2004 10:01:38:807AM1040310004Earl Marmarprogram to 1 MA

no TF dud
Mar 10 2004 10:20:17:007AM1040310005Earl Marmarno pcs changes
plasma
H-mode, almost steady RF
no ITB
confinement improves after 1.3 seconds
Mar 10 2004 10:34:23:497AM1040310006Earl Marmarask for higher RF power
no PCS changes

plasma

H-Mode, no ITB
Mar 10 2004 11:09:20:177AM1040310007Earl Marmardrop target density
nl_04 prog to 8e19 from 1e20

plasma
still no ITB
Mar 10 2004 11:09:47:457AM1040310008Earl Marmarno pcs changes

data acquisition problems

no power shot
Mar 10 2004 11:24:05:527AM1040310009Earl Marmarno pcs changes
plasma; disrupt at 1.09 s
nice 3MW RF pulse
H-mode, no ITB
Mar 10 2004 11:57:19:827AM1040310010Earl Marmarreload from shot 8 (computer problems)

increase RXL by 1 cm

plasma
definite ITB on this one
Mar 10 2004 12:13:24:617PM1040310011Earl Marmarincrease Ip prog to 1.15MA
plasma
H-mode looking more ELM freeish
no obvious ITB

lurch at segment switch (0.1 s) causing some concern
Mar 10 2004 12:39:27:987PM1040310012Earl Marmarraise nl_04 target to 1.1e20
plasma with nice ITB, steady RF
Mar 10 2004 12:39:51:707PM1040310013Earl Marmarno pcs changes
plasma
more RF power, ITB
Mar 10 2004 01:08:12:530PM1040310014Earl MarmarIp prog to 0.90 MA
nl_04 target prog to 0.9e20
plasma, ITB
Mar 10 2004 01:19:49:547PM1040310015Earl Marmarno pcs changes
plasma, ITB
RF trippy
Mar 10 2004 01:43:12:367PM1040310016Earl Marmarno pcs changes
plasma
RF trips; weak ITB
Mar 10 2004 02:00:13:797PM1040310017Earl MarmarIp prog to 1.35MA
nl_04 target prog to 1.2e20
TF current down to 174700A from 177200

plasma
computer problems after the shot
several back transitions
Mar 10 2004 02:53:39:490PM1040310018Earl Marmarno pcs changes
plasma, ITB
some data system problems, mostly sorted out after the shot
Mar 10 2004 02:54:47:053PM1040310019Earl Marmarno pcs changes
plasma
several back transitions, no obvious ITB
Mar 10 2004 03:13:48:630PM1040310020Earl MarmarIp prog to 1.25MA
Itf to -177200 from -174700
nl_04 target to 1.1e20 from 1.2e20

Ip got to ~65kA at 20 msec and then it died. B_r went quite negative.


Mar 10 2004 03:27:37:447PM1040310021Earl Marmaradd .5mT to B_R offset
plasma
several back transitions
no obvious ITB
Mar 10 2004 03:49:23:590PM1040310022Earl Marmarno pcs changes
ask for more RF power
plasma
maybe a weak ITB before back transition
Mar 10 2004 04:04:34:237PM1040310023Earl Marmarraise target nl_04 to 1.2e20 from 1.1e20
plasma
definite ITB
Mar 10 2004 04:15:59:727PM1040310024Earl Marmarraise target nl_04 to 1.35e20 from 1.2e20

fizzle; nothing obviously wrong with the fields or fill
Mar 10 2004 04:37:02:697PM1040310025Earl Marmarreduce BR_0 offset by .5mT
plasma
weak ITB?
Mar 10 2004 04:56:24:273PM1040310026Earl MarmarTF to -153000
nl_04 target to 1.2e20
ELM-freeish, many back-transitions, many trips
Mar 10 2004 05:07:44:057PM1040310027Earl Marmarreload from 1040310015
reduce I_p prog to .75MA
reduce nl_04 target to .8e20
fizzle

Engineering Operator Comments
ShotTimeTypeStatusComment
109:01:41:247AMPlasmaOk
209:22:29:463AMPlasmaOk
309:41:17:210AMPlasmaOk
409:59:12:723AMPlasmaOkNo TF
510:11:30:900AMPlasmaOk
610:27:22:720AMPlasmaOk
710:43:02:510AMTestBad
911:14:32:887AMTestBad
1011:47:43:453AMPlasmaOk
1112:02:01:833PMPlasmaOk
1212:20:12:470PMPlasmaOk
1312:33:24:477PMPlasmaOk
1412:56:04:027PMPlasmaOk
1501:10:43:393PMPlasmaOk
1601:26:46:903PMPlasmaOk
1701:44:25:383PMPlasmaOk
1802:17:08:870PMPlasmaOk
1902:41:31:173PMPlasmaOk
2003:02:48:927PMPlasmaOk
2103:19:25:793PMPlasmaOk
2203:36:02:837PMPlasmaOk
2303:53:21:800PMPlasmaOk
2404:10:43:937PMPlasmaOkAck failure just before shot but looked OK
2504:26:12:430PMPlasmaOk
2604:45:42:257PMPlasmaOk
2704:58:58:200PMPlasmaOk