Alcator C-Mod Run 1020712 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Steve Wukitch (shots 1-18)
Session Leader:Steve Wolfe (shots 1-18)

Operators
Session leader(s):Steve Wukitch,Steve Wolfe
Physics operator(s):Jim Irby
Engineering operator(s):Ed Fitzgerald,Gary Dekow

Engineering Operator Run Comment
Machine Cleaning with RF; SL:Wolfe/Wukitch; PO:Irby; EO:Dekow/Fitzgerald

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:37:15:303PM
Author: To Be Determined
EO: Dekow/Fitzgerald
SL: Wolfe/Wukitch
PO: Irby

Engineering setup for Friday 12 July 2002

Session leader: Wolfe/Wukitch
Physics operator: Irby

ECDC overnight in D2 at 2e-4 Torr, stopping by 08:00.
Set up for possible ECDC in D2 between shots.

Run begins at 10:00 (note the delayed start) and ends at 17:00.

Power systems the same as for shot 1020711006.

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)
leave J-Bottom as is Hybrid DISABLED (PG5)

Enable the following gate valves:

ECE

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Run Plan:

Continue cleanup of machine and run ICRF as possible. Run 4.5 T
shot or two for ECE tests/calibration. Compare startups. Complete
density scan. Run long/short length discharges for wall inventory
checks. This will be the last run before boronizaiton.



-------------------------------------------------------------------------------
Results:

Startup reliability today was the best we have had during this campaign.
Shot 01 was a dud because I did not ECDC following j-port vacuum conditioning
earlier in the morning. Ten minutes of ECDC and a Bz0 tweak produced a
full length plasma on shot 03 following a fizzle on shot 02. All remaining
attempts produced plasma. Several disruptions, with the plasma terminating
as early as .47 s, were correlated with attempts to push the density
above 1.0e20/m^2 on nl_04. It is not clear what is limiting the density
to this level. We were able to scan the density down reliably to
6e19/m^2. The H/D level rose as high as 15% at this density.

H/D at 1s:

0.6e20 12%,15%
0.8e20 12%
1.0e20 7-8%

We had many shots today with the pumpstack gatevalve toggle enabled.
So there is more data on wall loading/fueling etc. As we varied
the density, the after shot pressures ranged from 3 to 11 mTorr.

Amanda was able to obtain an ECE cal on a rampdown to 4.5 T.

We were unable to get any rf power into the machine today during a
plasma discharge. Work will continue after the run and on Monday to
get the rf systems online.

Too much gas on shot 06: 0.96 s plasma
shot 15 disrupted at 0.49 s
shot 16 disrupted at 0.47 s
shot 17 disrupted at 0.47 s

Duds 01
Fizzles 02
Plasmas 03,04,05,06,07,08,09,10,11,12,13,14,15,16,17,18

Session Leader Comments

Physics Operator Comments
Jul 12 2002 08:03:57:983AMJim IrbyDoing Hybrid Coldstart

No errors reported:

rtnode -- data loaded, A matrix responds
rtnode -- data loaded, M matrix responds
rtnode -- data loaded, PID matrix responds
RT_NODE Done
12-JUL-2002 07:45:11.65




Jul 12 2002 10:35:45:833AM1020712001Jim IrbyNL04 request dropped to 1.e20 --- all gas off past 1.0 s
Otherwise, PCS same as 1020711006

Dud

PO forgot to do ECDC after rf antenna conditioning --- will do 10 minutes ECDC before shot 02

Hard X-ray signal is working but with lots of 60 Hz pickup.
Jul 12 2002 11:02:42:350AM1020712002Jim Irby10 minutes of ECDC before shot

Fizzle --- nearly ran --- 40 kA

Pressure higher after ecdc
Br0 up +0.8 mT from shot 01

Bz0 too negative
Jul 12 2002 11:27:35:673AM1020712003Jim IrbyEF4 from -1330 to -1310

ECDC for 10 minutes

Plasma into rampdown

We have a very large hard x-ray signal ---- PMT gain too high

H/D 7.5% at 1.0 s ---- best yet

Jul 12 2002 11:52:56:420AM1020712004Jim IrbyNo PCS changes --- would like to adjust Br0, but it is jumping 0.5 mT shot-to-shot
ECDC for 10 minutes

Plasma into rampdown

Fields very close to last shot

H/D 7.2% at 1 s

Jul 12 2002 12:24:22:787PM1020712005Jim IrbyRepeat
10 minutes of ECDC

Plasma into rampdown

H/D at 7.8%

Jul 12 2002 12:51:41:430PM1020712006Jim IrbyECDC for about 10 minutes

Density from 1.0 to 1.2e20/m^2 at .5 s

Disruption at 0.96 s ---- will give up on higher density

I bypassed the hard x-ray amplifier and went directly into the incaa --- now we have positive going spikes as
we should

H/D 6 to 7% before disruption
Jul 12 2002 01:15:16:437PM1020712007Jim IrbyECDC for 10 minutes

Dropped density back to 1.e20 /m^2

Bt ramped down to 4.5 T after 0.1 s

Plasma into rampdown

Field ramped down to 4.54 T --- PO needs a better calculator

H/D 8.3% at 1.0 s

CII at .004 for the last couple of shots
Jul 12 2002 01:31:14:300PM1020712008Jim IrbyNo changes

ECDC for 10 minutes

Plasma into rampdown

H/D 7.9% at 1 s

Amanda is happy with the 4.5 T data --- back to 5.3 next shot

Hard X-rays and neuts have spike at 0.26 s.
Jul 12 2002 01:59:12:070PM1020712009Jim IrbyECDC for 10 minutes

Bt back to 5.3 T

Nice plasma

H/D 8% at 1s
Jul 13 2002 11:22:41:340PM1020712010Jim IrbyPlasma into rampdown

H/D 7.9% at 1 s

Pressure after shot about 7.3 mTorr

Gatevalve closure enabled
Jul 12 2002 02:44:53:673PM1020712011Jim IrbyNo PCS changes.

Gatevalve closure enabled

10 minutes of ECDC

Had a little antenna vacuum conditioning before the shot

Plasma into rampdown

pressure to 7.4 mTorr after shot

H/D 7.9% again --- next shot will be w/o ECDC
Jul 12 2002 03:15:01:180PM1020712012Jim IrbyDropped density request to 8e19/m^2

No ECDC

Added 10 ms integrator to hard x-ray signal

Plasma to rampdown --- got the request density

H/D up to 12% at 1 s ---- density or lack of ECDC?

pressure after shot 3.7 mTorr

Jul 12 2002 03:28:43:010PM1020712013Jim IrbyDropped density request to 6e19/m^2 --- continue gatevalve toggle

rf guys have not been able to condition d after all --- problem with an enable signal

No ECDC before shot

Plasma into rampdown ---- got density request

H/D 15% at 1 s

pressure after shot 2 mTorr
Jul 12 2002 03:52:57:673PM1020712014Jim IrbyDensity request to 1.1e20/ m^2, but bring up density more slowly

Plasma into rampdown --- density barely made the request at 1 s

H/D 11% at 1s

pressure to 10.5 mTorr
Jul 12 2002 04:16:12:807PM1020712015Jim Irbyrepeat to see in H/D stays high or starts down

Disruption at 0.5 s --- ecdc before next shot

Jul 12 2002 04:31:09:717PM1020712016Jim IrbyECDC for 10 minutes before shot

Density request brought up more quickly

Removed integrator from hard x-ray signal

Disruption at 0.47 s --- give up "high" density attempt
Jul 12 2002 04:51:42:437PM1020712017Jim IrbyReloaded shot 13 and then set density request to 1.e20/m^2

Disabled gatevalve toggle

ECDC for 10 minutes

Another disruption: .47 s

Jul 12 2002 05:21:24:620PM1020712018Jim IrbyDensity request to 6e19/m^2

Plasma to rampdown --- got requested density

H/D 11% at 1 s

Engineering Operator Comments
ShotTimeTypeStatusComment
110:15:49:960AMPlasmaOk
210:38:22:480AMPlasmaOk
311:04:11:743AMPlasmaOk
411:28:44:533AMPlasmaOk
511:54:22:157AMPlasmaOk
612:25:29:853PMPlasmaOk
712:52:51:383PMPlasmaOk
801:17:09:177PMPlasmaOk
901:40:13:463PMPlasmaOk
1002:05:22:957PMPlasmaOk
1102:31:56:800PMPlasmaOk
1202:51:18:080PMPlasmaOk
1303:16:59:903PMPlasmaOk
1403:40:27:897PMPlasmaOk
1503:58:26:437PMPlasmaOk
1604:19:45:283PMPlasmaOk
1704:43:07:650PMPlasmaOk
1805:05:26:577PMPlasmaOk