Alcator C-Mod Run 1010516 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Steve Wolfe (shots 1-15)

Operators
Session leader(s):Steve Wolfe
Physics operator(s):Jim Irby
Engineering operator(s):Gary Dekow,Bill Cochran

Engineering Operator Run Comment
Plasma Startup

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:26:117PM
Author: To Be Determined
Session Leader's Summary for Wednesday, May 16, 2001

Plasma Startup
DNB/MSE Testing

SL: wolfe
PO: Irby
EO: Cochran/Dekow

We started from last night's "successful" plasma shot, 1010515034,
and immediately reproduced it (shot 1). This was followed by several
fizzles (#2-4) during which the OH2L coax resistance climbed to ~2uOhm.
This behavior was very similar to that observed last March (see notes
from 1000321, 1000322, 1000328).

Shots #5-8 were OH/TF "tests" to try to reverse the increasing resistance
trend. Shot #5 was taken with the OH's in the wrong (forward) direction
because of a communication failure, and actually gave higher resistance
readings (2.7uOhm). Shots #6-8 were run as intended, with 150KA tf and
10kA reverse bridge on the OH's. However, the resistance did not come down
as hoped.

We then allowed the OH to warm up for ~2.5 hours, while carrying out ECDC,
and then cooled down again. The OH temperature only got up to -150C or so,
as compared to -75C for an overnight warmup. Shot #9 was a repeat TF/OH test.
The OH2L coax resistance remained high, so we decided to proceed with
the DNB/MSE tests that were the second part of the run plan.

Shots #10-11 were TF-only shots under PLC control with the standard 20msec
pre-puff from B-top (segment 1) only. Due to a miscommunication, the fizzle
detector was set for 0.28 sec instead of 0.38, with the beam starting at
0.2, so these shots had a shortened beam pulse.

This was corrected for shot#12 and the pre-puff was doubled to ~40msec to
increase the MSE signal. The total presure at the time of the beam went up to
.14mTorr. Shots #13-15 were also done at this pressure, but the beam was
faulting on most of these as Ned attempted to raise the voltage.

Signals were seen on the BES and MSE. Discussions with Howard and Earl
suggested that most of the signal seen on the outer radial channels of the MSE
comes from the half energy component, which does seem to fall within the
filter bandpass for these channels. This remains to be confirmed by Howard
by calculations using the actual filter functions and viewing angles.

Operating between shots, the RF group got both D and E antennas up to
30kV.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:12:990PM
Author: To Be Determined
Run 1010516: MSE/DNB Calibrations and Plasma Cleanup

SL: Wolfe
PO: Irby
EO: Cochran, Dekow

Engineering setup:

ECDC in D2 at 2e-4 Torr, overnight.

Gas setup:
fill B-top with 6 psi of D2 Hybrid Enable
fill B-side lower with 1 psi of Ar Hybrid DISABLED
fill B-side upper with nothing Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid Enable
fill J-bottom with nothing Hybrid DISABLED


PLease have XMTR 1 and 2 warmed up
by run startup (9:00)

The network analyzer should be warming up
by the 1/2 switches in the power room.

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


Results:

We had originally planned to run the DNB/MSE tests first and then
move on to the plasma cleanup run. However, Ned wanted time to
condition the beam more. So we started off with plasma attempts
instead. Shot 1 ran for 0.17 s with over 500 kA of plasma current.
The following 3 shots were fizzles even though we had up to 30 minutes
between shots and some ECDC. On shot 4 the OH2L coax resistance rose
above 1 uOhm and we started TF/OH only shots to try to bring it back down.
This problem has occurred during all plasma startups after an extended
shutdown and will require some warm up time to fix.

On shot 10 we began TF only MSE/DNB shots with background gas provided
by the b-top prefill valve.


Score:

fizzles 3
plasmas 1
OH tests 5
MSE/DNB 6

Total 15


Details:

Entry display output on Wed May 16 17:15:29 2001


----------------------------------------------------------------------------
1010516xxx irby DISCHARGE_CLEAN May 16 2001 7:35:05:136AM
. . . . . . . . . . . . . . . . . . . .
Overnight ECDC in D2 at 2e-4 Torr
----------------------------------------------------------------------------
*** Coldstart successful ***
----------------------------------------------------------------------------
1010516001 irby PHYSICS_OPERATOR May 16 2001 9:17:16:670AM
. . . . . . . . . . . . . . . . . . . .
Start from yesterday's plasma shot (34)

Plasma for 168 ms.

oh1: 0.1770 uohm
oh2u: 0.3400 uohm
oh2l: 0.1997 uohm

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): 2.0337 -10.9371 -23.9079 -70.6255
dIp/dt (kA/ms): -1.2728 -2.5422 -2.0346 -5.8485
pressure (mTorr): 0.0579 0.0634 0.0573 0.0542
Bz0 (mT): -5.7705 -3.3503 -1.1019 18.6702
Br0 (mT): -1.0124 -1.3053 -0.9962 -1.9338

----------------------------------------------------------------------------
1010516002 irby PHYSICS_OPERATOR May 16 2001 9:42:33:923AM
. . . . . . . . . . . . . . . . . . . .
DNB has asked to have their TF only shots late in the day. So
we will continue trying to make plasmas. RF and DNB will be
firing between shots.

Fizzle as expected

oh1: 0.1687 uohm
oh2u: 0.2760 uohm
oh2l: 1.0931 uohm

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): 2.0564 -10.9144 -21.3138 -16.1482
dIp/dt (kA/ms): -1.2705 -2.2912 -0.7641 0.2521
pressure (mTorr): 0.0586 0.0606 0.0606 0.0663
Bz0 (mT): -4.6093 -2.9174 -0.6716 17.5363
Br0 (mT): -1.2523 -1.2541 -1.9352 -1.6222

----------------------------------------------------------------------------
1010516003 irby PHYSICS_OPERATOR May 16 2001 10:11:26:906AM
. . . . . . . . . . . . . . . . . . . .
Trying to stick to a 20 minutes shot cycle. After this shot
we will start ECDC in D2 at 2e-4 Torr at T=10 minutes. The DNB
and ICRF guys will condition up to T=10.

Pressure at init about 4e-7 Torr

Fizzle again.

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): 2.0337 -10.9598 -23.9306 -16.1482
dIp/dt (kA/ms): -1.1467 -2.4161 -1.0151 0.0011
pressure (mTorr): 0.0579 0.0573 0.0613 0.0613
Bz0 (mT): -4.0928 -1.4752 0.4329 16.9260
Br0 (mT): -0.7751 -1.3958 -1.4507 -2.0289

ICRF has finished conditioning for today.

oh1: 0.1805 uohm
oh2u: 0.5351 uohm
oh2l: 1.8672 uohm

If oh2l rises on next shot we will do a tf/oh test.

----------------------------------------------------------------------------
1010516004 irby PHYSICS_OPERATOR May 16 2001 10:33:46:066AM
. . . . . . . . . . . . . . . . . . . .
Had 5 minutes ECDC in D2

Fizzle

oh1: 0.1808 uohm
oh2u: 0.5958 uohm
oh2l: 2.0309 uohm

Setting up for PLC TF/OH test

----------------------------------------------------------------------------
1010516005 irby PHYSICS_OPERATOR May 16 2001 10:55:24:333AM
. . . . . . . . . . . . . . . . . . . .
Will run 10kA OH test, positive current, TF at 5.3 T.

Woops ---- wrong OH direction --- positive bridge, not positive current.

oh1: 0.2014 uohm
oh2u: 0.4312 uohm
oh2l: 2.8381 uohm
----------------------------------------------------------------------------
1010516006 irby PHYSICS_OPERATOR May 16 2001 11:04:09:266AM
. . . . . . . . . . . . . . . . . . . .
Try TF/OH test again but with positive 10kA OH current


oh1: 0.1469 uohm
oh2u: 0.3386 uohm
oh2l: 2.5261 uohm

Little better. Will repeat.
----------------------------------------------------------------------------
1010516007 irby PHYSICS_OPERATOR May 16 2001 11:32:37:936AM
. . . . . . . . . . . . . . . . . . . .
TF/OH repeat shot

oh1: 0.2168 uohm
oh2u: 0.4446 uohm
oh2l: 2.7045 uohm

Didn't go down, and was rising during the shot.

----------------------------------------------------------------------------
1010516008 irby PHYSICS_OPERATOR May 16 2001 11:40:54:730AM
. . . . . . . . . . . . . . . . . . . .
Another try with TF/OH

oh1: 0.2102 uohm
oh2u: 0.4481 uohm
oh2l: 2.7700 uohm

We will stop until 14:00 to let the OH warm up followed by another
cooldown.


----------------------------------------------------------------------------
1010516009 irby PHYSICS_OPERATOR May 16 2001 3:35:37:060PM
. . . . . . . . . . . . . . . . . . . .
After warming up OHs to about -150 from -200 C we are trying
the TF/OH test again.

oh1: 0.1775 uohm
oh2u: 0.4241 uohm
oh2l: 2.8872 uohm

We are going to TF only shots for DNB/MSE. Will return to TF/OH
at end of run. Probably will require warmup of OH to get us back
down.
----------------------------------------------------------------------------
1010516010 irby PHYSICS_OPERATOR May 16 2001 3:46:22:356PM
. . . . . . . . . . . . . . . . . . . .
Preparing for DNB/MSE:
. turned off segment 2
. fizzle 0.38 s
. plc control of TF
. only b-top gas enabled

MSE sees some light.
----------------------------------------------------------------------------
1010516011 irby PHYSICS_OPERATOR May 16 2001 4:00:31:473PM
. . . . . . . . . . . . . . . . . . . .
Repeat of shot 10

Ned noticed that the fizzle detector is going too early. Bill C
should have it fixed for the next shot.
----------------------------------------------------------------------------
1010516012 irby PHYSICS_OPERATOR May 16 2001 4:15:25:400PM
. . . . . . . . . . . . . . . . . . . .
Doubled prepuff window: took pressure up to 0.14 mT from 0.1 mT at
time of beam.
----------------------------------------------------------------------------
1010516013 irby PHYSICS_OPERATOR May 16 2001 4:40:53:676PM
. . . . . . . . . . . . . . . . . . . .
Repeat

No beam --- PLC bells


----------------------------------------------------------------------------
1010516014 irby PHYSICS_OPERATOR May 16 2001 4:48:03:420PM
. . . . . . . . . . . . . . . . . . . .
Repeat

No beam --- arc down
----------------------------------------------------------------------------
1010516015 irby PHYSICS_OPERATOR May 16 2001 5:09:47:250PM
. . . . . . . . . . . . . . . . . . . .
no beam


Session Leader Comments
May 16 2001 09:16:11:290AM1010516001Steve Wolfeshot#1: Plasma, 170msec resistive, like 1010515034. Hard xrays.
Joe reconnected Ha2 bright diode at c-port.
TCI analysis still not running.
EFIT worked this time, with the kludged def in VLOOP.

Next shot: try again.
Joe may have fixed CII, it may not be pointed right.
May 16 2001 09:28:40:403AM1010516002Steve Wolfeshot#2: fizzle. Surprise, suprise.
CII working, claims .003, but it may not be aligned;
TCI analysis ran ok that time, Jim says he didn't change anything.
Joe reported the diode mount was loose.
Still a nice breakdown, it just needs to clean up.
May 16 2001 09:50:32:700AM1010516003Steve Wolfeshot#3: another fizzle.

next shot: wait ten minutes, ecdc for five minutes, shoot at 20minutes

May 16 2001 11:40:24:247AM1010516008Steve Wolfeshot#8: We've done a series of OH/TF only shots to try to bring down
the OH2L coax resistance, but it doesn't seem to be helping.

We will go to ecdc, allow the oh to warm up some, then cool back down
and try again.
Probably off-line until ~14:30 or so, unless the dnb is ready for their
tf tests before then.
May 16 2001 03:39:53:740PM1010516009Steve Wolfeshot#9: OH2L resistance is still high.


Next shot:
Go on to TF-only tests for Ned:
TF PLC 150KA to .38sec, fd to .38sec
pg4 puff in seg1 only.

May 16 2001 04:15:13:370PM1010516012Steve Wolfeshot #12: TF + 40msec pre-puff, with beam.
ratiomatic reads .13mtorr at t=0. 14 at the start of the beam pulse
May 16 2001 04:30:58:630PM1010516013Steve Wolfeshot #13: tried raising the beam voltage. Faulted?

Physics Operator Comments
May 16 2001 08:27:21:577AMJim IrbyEngineering setup for 1010516: Plasma Startup

ECDC in D2 at 2e-4 Torr, overnight.

Start from shot 1001205001 (5.3 T, 800 kA)

Gas setup:
fill B-top with 6 psi of D2 Hybrid Enable
fill B-side lower with 1 psi of Ar Hybrid DISABLED
fill B-side upper with nothing Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid Enable
fill J-bottom with nothing Hybrid DISABLED


PLease have XMTR 1 and 2 warmed up
by run startup (9:00)

The network analyzer should be warming up
by the 1/2 switches in the power room.

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

We will start from last shot from yesterday, 1010515034, in which we had a
200 ms long 500kA plasma.

shot: 1010515034

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): 2.0109 -10.9598 -21.3365 -57.6547
dIp/dt (kA/ms): -1.1445 -2.5433 -2.2901 -5.0888
pressure (mTorr): 0.0701 0.0701 0.0701 0.0641
Bz0 (mT): -4.7395 -2.8362 -0.2035 17.1340
Br0 (mT): -1.4418 -1.5817 -1.6680 -2.5308

We will be setup for ECDC between shots

*** Coldstart successful ***
May 16 2001 09:17:16:670AM1010516001Jim IrbyStart from yesterday's plasma shot (34)

Plasma for 168 ms.

oh1: 0.1770 uohm
oh2u: 0.3400 uohm
oh2l: 0.1997 uohm

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): 2.0337 -10.9371 -23.9079 -70.6255
dIp/dt (kA/ms): -1.2728 -2.5422 -2.0346 -5.8485
pressure (mTorr): 0.0579 0.0634 0.0573 0.0542
Bz0 (mT): -5.7705 -3.3503 -1.1019 18.6702
Br0 (mT): -1.0124 -1.3053 -0.9962 -1.9338

May 16 2001 09:42:33:923AM1010516002Jim IrbyDNB has asked to have their TF only shots late in the day. So
we will continue trying to make plasmas. RF and DNB will be
firing between shots.

Fizzle as expected

oh1: 0.1687 uohm
oh2u: 0.2760 uohm
oh2l: 1.0931 uohm

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): 2.0564 -10.9144 -21.3138 -16.1482
dIp/dt (kA/ms): -1.2705 -2.2912 -0.7641 0.2521
pressure (mTorr): 0.0586 0.0606 0.0606 0.0663
Bz0 (mT): -4.6093 -2.9174 -0.6716 17.5363
Br0 (mT): -1.2523 -1.2541 -1.9352 -1.6222

May 16 2001 10:11:26:907AM1010516003Jim IrbyTrying to stick to a 20 minutes shot cycle. After this shot
we will start ECDC in D2 at 2e-4 Torr at T=10 minutes. The DNB
and ICRF guys will condition up to T=10.

Pressure at init about 4e-7 Torr

Fizzle again.

Time (ms): 0 5 10 25
----------------------------------------
Ip (kA): 2.0337 -10.9598 -23.9306 -16.1482
dIp/dt (kA/ms): -1.1467 -2.4161 -1.0151 0.0011
pressure (mTorr): 0.0579 0.0573 0.0613 0.0613
Bz0 (mT): -4.0928 -1.4752 0.4329 16.9260
Br0 (mT): -0.7751 -1.3958 -1.4507 -2.0289

ICRF has finished conditioning for today.

oh1: 0.1805 uohm
oh2u: 0.5351 uohm
oh2l: 1.8672 uohm

If oh2l rises on next shot we will do a tf/oh test.

May 16 2001 10:33:46:067AM1010516004Jim IrbyHad 5 minutes ECDC in D2

Fizzle

oh1: 0.1808 uohm
oh2u: 0.5958 uohm
oh2l: 2.0309 uohm

Setting up for PLC TF/OH test

May 16 2001 10:55:24:333AM1010516005Jim IrbyWill run 10kA OH test, positive current, TF at 5.3 T.

Woops ---- wrong OH direction --- positive bridge, not positive current.

oh1: 0.2014 uohm
oh2u: 0.4312 uohm
oh2l: 2.8381 uohm
May 16 2001 11:04:09:267AM1010516006Jim IrbyTry TF/OH test again but with positive 10kA OH current


oh1: 0.1469 uohm
oh2u: 0.3386 uohm
oh2l: 2.5261 uohm

Little better. Will repeat.
May 16 2001 11:32:37:937AM1010516007Jim IrbyTF/OH repeat shot

oh1: 0.2168 uohm
oh2u: 0.4446 uohm
oh2l: 2.7045 uohm

Didn't go down, and was rising during the shot.

May 16 2001 11:40:54:730AM1010516008Jim IrbyAnother try with TF/OH

oh1: 0.2102 uohm
oh2u: 0.4481 uohm
oh2l: 2.7700 uohm

We will stop until 14:00 to let the OH warm up followed by another
cooldown.


May 16 2001 03:35:37:060PM1010516009Jim IrbyAfter warming up OHs to about -150 from -200 C we are trying
the TF/OH test again.

oh1: 0.1775 uohm
oh2u: 0.4241 uohm
oh2l: 2.8872 uohm

We are going to TF only shots for DNB/MSE. Will return to TF/OH
at end of run. Probably will require warmup of OH to get us back
down.
May 16 2001 03:46:22:357PM1010516010Jim IrbyPreparing for DNB/MSE:
. turned off segment 2
. fizzle 0.38 s
. plc control of TF
. only b-top gas enabled

MSE sees some light.
May 16 2001 04:00:31:473PM1010516011Jim IrbyRepeat of shot 10

Ned noticed that the fizzle detector is going too early. Bill C
should have it fixed for the next shot.
May 16 2001 04:15:25:400PM1010516012Jim IrbyDoubled prepuff window: took pressure up to 0.14 mT from 0.1 mT at
time of beam.
May 16 2001 04:40:53:677PM1010516013Jim IrbyRepeat

No beam --- PLC bells


May 16 2001 04:48:03:420PM1010516014Jim IrbyRepeat

No beam --- arc down
May 16 2001 05:09:47:250PM1010516015Jim Irbyno beam

Engineering Operator Comments
ShotTimeTypeStatusComment
109:03:55:617AMPlasmaOk
209:23:46:583AMPlasmaOk
309:46:20:040AMPlasmaOk
410:19:05:340AMPlasmaOkAll PS Fired okay, except OH2L Coax increased to 2.03uohms
510:43:09:253AMTestBadOH Power Supplies setup with wrong polarity.
610:56:24:693AMTestOkOH Coax down to 2.5210uohm
711:14:32:440AMTestOkOH Coax Test
811:28:26:303AMTestOkOH Coax Test
903:23:53:010PMTestOkOH Coax Test
1003:41:17:507PMTestOkTF only
1103:54:34:433PMTestOkTF only
1204:10:27:393PMTestOkTF only
1304:27:35:140PMTestOkTF Only Test
1404:42:06:410PMTestOkTF Only Test
1504:57:49:670PMTestOkTF Only Test