Alcator C-Mod Run 1020701 Information

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Miniproposals
Miniproposal:298a
Date Filed: 5/20/2002
Title:C-Mod Plasma Startup
First Author:Jim Irby
Session Leader:Jim Irby (shots 1-23)

Operators
Session leader(s):Jim Irby
Physics operator(s):Dmitri Mossessian
Engineering operator(s):Bill Byford,Bill Cochran,Gary Dekow

Engineering Operator Run Comment
MP298A Startup/Condition; SL:Irby; PO:Mossessian; EO:Dekow/Cochran/Byfor

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:29:007PM
Author: To Be Determined
Run Summary for 1020701:Plasma Conditioning Continued (298A)

EO: Byford/Cochran/Dekow
PO: Mossessian
SL: Irby

We began by producing lower single null plasmas with a density request
of 3e19/m^2 in an attempt to see how H/D would respond to low densities.
Several data system problems kept us from getting H/D data on the first
couple of plasma shots. However, on shot 05, the H/D was very much the
same as the high density case from last week at about 20%.

On shot 08 we changed to a double null configuration. We maintained a
flat density of 3e19/m^2 with about 10 Torr-l/s of gas injection required.
Unfortunately the density was so low we did not get good H/D
data; we estimate about 30%. For shot 09 we increased the request
to 4e19/m^2 to improve the H/D signal. The density was again well
maintained with about 12 Torr-l/s of gas required. H/D was about 30%
late in the shot where the signals were better.

ECDC was run before the fizzle on shot 10 in an effort to determine how
much ECDC helps reduce H/D. When we got a plasma on shot 11 the H/D was
lower and somewhat less gas was required to maintain the density.
The gatevalves were closed in pulse for this shot so we were able to
measure the gas inventory at about 4 Torr-l (4000l at 1 mTorr). Note that
the gas pressure continued to increased past the 12 s data window. On a
dud (shot 16) the gas pressure rose to 0.5 mTorr quickly and actually
decreased somewhat by 12 s. Outgassing from the walls after a plasma shot
may explain this effect. On high density shots the pressure rose to 5 to
7 mTorr indicating about 20 to 28 Torr-l of gas.

Ian calculates that the injected gas inventory is consistent with
the pressure rise after the shot. However, later in the run, Bruce found
a shot with about 21 Torr-l of gas input but 28 Torr-l of gas after the shot.
We need to check various calibrations before we can trust these results.

On shot 17 we increased the density request to 1e20/m^2 in the double null
configuration. The H/D was 16% at 1.5 s. Shot 18 confirmed this number.

After several fizzles, we were able to get a high density lower null
discharge to compare with the high density double null case. The
H/D in this case only rose to 12% at 1.5 s.

We will continue tomorrow with what I hope is the final day of
conditioning.

Lost all the data for shot 12, a no power shot, with MATROX hang
The fizzle on shot 10: gatevalves were closed giving too high a prefill


Duds 01,16

Plasmas 02,03,05,06,07,08,09,11,14,15,17,18,23

Fizzles 10,19,20,21,22

Data System 04,12,13

Physics Operator Summaries
Entered: Jul 7 2004 04:37:15:210PM
Author: To Be Determined
Physop summary for 1020701:

Startup and conditionning.

SL. Irby
PO Mossessian

Summary:

Strange day. Things kept breaking down, CAMAC was not very reliable, overall 13 plasmas out of 23 shots.
First we tried to see what affects H/D ratio - gas puff, double/single null
configuration, or something else. We were going to start with single null, no gas puff, then go to double null
First shot was a dud for no apparent reason. On the next two shots H/D did not work. Then
there was a fizzle/dud ? - all the data was lost. Shots 8 to 18 - double null with various densities. Then series of fizzles,
and only the last shot (23) was more or less succesfull single null, high density shot.

Overall:

23 shots
13 plasmas
2 duds
8 fizzles



-----------------------------------------------------------------------------
1020701001

Load shot 1020628023. In segment 2 set density feedback to 3e19.
Make sure the gas puff is 0 in segment 2.

Dud.

Wolfe thinks the prefill is a little too low. It is also possible that
firing J-port at 9:30 had some undesirable effect.

Try 10 min ECDC before the next shot. Prefill up 5 msec to 28 msec
It is possible that there is a fault in the sparker.
-----------------------------------------------------------------------------
1020701002

Plasma. Good shot. Density stays at 4e19 up to ~1.2 sec, then ramps down.
No H/D though - some CAMAC problems.

Next shot - repeat shot 2. Lower pulse_gas_3 a bit in segment1 to get rid of the
hump in density at .24
-----------------------------------------------------------------------------
1020701003

Nice plasma. Density comming from the walls - stays at 5e19, gas puff is 0.
Problems with CAMAC, no H/D.

Next shot - repeat last shot.
-----------------------------------------------------------------------------
1020701004

Fizzle or dud - no data at all.

Next shot - repeat with no change.
-----------------------------------------------------------------------------
1020701005

H/D signal is apparently fixed, the problems have been caused by
a software change between shots 1 and 2.

Plasma. Density ramps up to 5.4e19 without gas. H/D is 20%, constant
throughout the shot.

Next shot - repeat with no change. Stop ECDC between shots.
-----------------------------------------------------------------------------
1020701006

Plasma. Br may be a little low. Density 5e19. H/D is 20% const

For next shot - Br offset 0.001 -. 0.0015.
Go to double null - load segment 2 from 1020621020, programmed nl to 3e19
-----------------------------------------------------------------------------
1020701007

Plasma. But single null - PO mistake - the shot I loaded was a single null.
Density was lower 4e19, probably because of shorter ECDC before the shot.
H/D was 40%

Next shot - loaded segment 2 from 1020628006 - real double null now.
Program density to 3e19
-----------------------------------------------------------------------------
1020701008

Plasma. Double null. Density stays at 3e19 with a lot of gas puffing.
Bruce says the walls are pumping.
H/D signal is very noisy.

For next shot - density up to 4e19, no other changes.
-----------------------------------------------------------------------------
1020701009

Good plasma. Density at 4e19 as programmed.
H/D signal is noisy, ~50% average.

Next shot - no changes in PCS. ECDC between shots for 10 min.
-----------------------------------------------------------------------------
1020701010

Fizzle. Too much gas - 0.1 instead of 0.085 mtor F-side pressure. Probably
because of ECDC. Also, the gate valves were shut before the shot.

For next shot - prepuff from 0.28 to 0.23. No other PCS changes.
No ECDC between shots this time
-----------------------------------------------------------------------------
1020701011

Plasma. Slightly lower gas puff during the shot. Density 4e19.
H/D is lower, average ~ 20%.

For next shot - repeat previous shot with ECDC between shots again.
-----------------------------------------------------------------------------
1020701012

No power shot
-----------------------------------------------------------------------------
1020701013

Repeating shot 11.

No power shot
-----------------------------------------------------------------------------
1020701014

Repeating shot 11.

PLasma. Looks very similar to shot 11

Next shot - go to higher density 1e20. No ECDC between shots.
-----------------------------------------------------------------------------
1020701015

Plasma. PO forgot to load the higher density configuration into PCS.

Next shot - another attempt to go to 1e20.
-----------------------------------------------------------------------------
1020701016

Dud. Sparker did not spark.

Next shot - no change
-----------------------------------------------------------------------------
1020701017

Good plasma. Density 1e20, H/D about 16%.

Next shot - no changes. ECDC between shots for 5 min.
-----------------------------------------------------------------------------
1020701018

Good plasma. Same as shot 17. Density 1e20, H/D is better - about 10%.

Next shot - go back to single null. Loaded segment 2 from shot 1020701006.
Loaded density trace into segment 2 from 1020701018 (1e20)
-----------------------------------------------------------------------------
1020701019

Fizzle. F-side pressure gauge died.

Next shot - repeat with no change
-----------------------------------------------------------------------------
1020701020

Fizzle again.

Next shot - drop the prepuff 23 msec -> 20 msec
-----------------------------------------------------------------------------
1020701021

Fizzle again.

Next shot - lower Bz 1 mT. IC_EF4 -1330 -> -1350
-----------------------------------------------------------------------------
1020701023

Plasma. Barely made it at startup. Bz too low. H/D is slightly
lower than on shot 18 - starts from 10% but goes up to ~13% only
by the end of the shot

End of run


Session Leader Comments
Jul 1 2002 11:05:19:780AM1020701001Jim IrbyDud ---- ECDC before next shot
Sparker was not the same as last Friday
RF had been doing conditioning shots
Jul 1 2002 11:35:39:063AM1020701002Jim IrbyNice plasma into rampdown

Jul 1 2002 12:30:05:177PM1020701004Jim IrbyDUD or Fizzle --- not clear --- no data

H to D should be back for the next shot ---- SOFTWARE CHANGE HAS BEEN REVERSED

We lost the HYBRID data earlier because of a CAMAC power supply failure

We have asked that the RF be off for the next shot
Jul 1 2002 01:00:12:177PM1020701005Jim IrbyNo RF
A14 software regressed

ECDC before the shot

H/D about 20% and flat

Jul 1 2002 01:09:45:270PM1020701006Jim IrbySome ECDC before the shot

Plasma

H/D 20% again
Jul 1 2002 01:20:07:037PM1020701007Jim IrbyPlasma

No ECDC

This was not a double null shot ---

H/D 40%

Carbon II has been low all day .003
Jul 1 2002 01:46:49:623PM1020701008Jim IrbyPlasma

No ECDC

Double null

No RF

H/D very noisy 35 to 65%

Maintained density at 3e19/m^2 with 10 torr-l/s of gas --- very flat

Jul 1 2002 02:07:50:703PM1020701009Jim IrbyRepeat except for density request up to 4e19 / m^2 to make H/D more reliable
No ECDC
Plasma into rampdown
Higher well controlled density ---- puff up a couple of torr-l/s

H/D still very noisy -- 20 to 80%

Will have ECDC for next shot (10 minutes)
Jul 1 2002 02:37:57:163PM1020701010Jim IrbyRepeat last shot with ECDC for 10 minutes before the shot
Enabled LPI gatevalve for this shot
Enabled pumping stack gatevalve toggle

Fizzle

Fill pressure too high ---- ECDC plus gatevalve closed?

Jul 1 2002 02:53:42:407PM1020701011Jim IrbyRepeat of 10 but lower prefill --- no extra ECDC

Plasma into rampdown

Pressue 5e-4 Torr on IGT after the shot

H/D 16 to 30% ---- ECDC?

Somewhat less gas required to maintain density

Pressure rose to about 1 mTorr at 12 s and was still rising --- indicates about 4 torr-l of gas

Jul 1 2002 03:20:01:023PM1020701012Jim IrbyMHD digitizers turned off to improve shot cycle

Repeat last shot with 10 minutes of ECDC before the shot

Lost data because of MATROX hang.
Jul 1 2002 04:06:05:690PM1020701015Jim IrbyDid not load new high density --- so we repeated 14 ---
Plasma to rampdown
H/D 20 to 30%
About 10 to 12 Torr-l/s required to maintain density

Jul 1 2002 04:45:42:220PM1020701017Jim IrbyTry for high density again --- 1e20/m^2
Plasma
5 minutes of ECDC
H/D 15% rising to 18%
Pressure high at 5.5 mTorr at 12 s ---- starts rising again at 8 s?

About 20 Torr-l/s of gas required to maintain density until 1.2 s when the density began to
ris on its own.


Jul 1 2002 05:07:37:533PM1020701018Jim IrbyRepeat
LPI firing pellet at 1.7 s
5 minutes ECDC
Plasma to rampdown

Pressure after shot rises to 7 mTorr

H/D 16% at 1.5 s

Jul 1 2002 05:19:20:147PM1020701019Jim Irby5 minutes of ECDC before shot
Attempt at lower null plasma --- 1e20 /m^2
Fizzle

MKS gauges about .4 mTorr at 12 s

We lost G-side ratiomatic

Jul 1 2002 05:29:56:347PM1020701020Jim Irby5 minutes of ECDC
try again --- fizzle

Will drop prefill for next shot
Jul 1 2002 05:41:49:837PM1020701021Jim Irbytry again --- Dmitri will try dropping the prefill a little

another fizzle ---- Ian suggests Bz0
Jul 1 2002 05:58:57:923PM1020701022Jim IrbyAnd we try again --- no ECDC before the shot

fizzle

Physics Operator Comments
Jul 1 2002 09:21:10:153AMSteve Wolfe09:15 Dmitri isn't in yet, I'll go ahead and do a coldstart, in view
of the problems encountered last week.

All matrices respond.
hloader log shows no errors.
Jul 1 2002 10:01:33:120AM1020701001Dmitri Mossessian9:50 AM - Wolfe did coldstart

We will try to see what affects H/D ratio - gas puff, double/single null
configuration, or something else.

Start with single null, no gas puff, then go to double null

We will try single null low density shot first.
Load shot 1020628023. In segment 2 set density feedback to 3e19.
Make sure the gas puff is 0 in segment 2.
Jul 1 2002 10:48:09:020AM1020701001Dmitri MossessianDud.
Wolfe thinks the prefill is a little too low. It is also possible that
firing J-port at 9:30 had some undesirable effect.

Try 10 min ECDC before the next shot. Prefill up 5 msec to 28 msec
It is possible that there is a fault in the sparker.
Jul 1 2002 11:11:17:243AM1020701002Dmitri MossessianPlasma. Good shot. Density stays at 4e19 up to ~1.2 sec, then ramps down.
No H/D though - some CAMAC problems.

Next shot - repeat shot 2. Lower pulse_gas_3 a bit in segment1 to get rid of the
hump in density at .24
Jul 1 2002 11:16:50:957AM1020701002Dmitri MossessianPlasma. Good shot. Density stays at 4e19 up to ~1.2 sec, then ramps down.
No H/D though - some CAMAC problems.

Next shot - repeat shot 2. Lower pulse_gas_3 a bit in segment1 to get rid of the
hump in density at .24
Delayed because of hybrid problems
Jul 1 2002 11:57:24:487AM1020701003Dmitri MossessianNice plasma. Density comming from the walls - stays at 5e19, gas puff is 0.
Problems with CAMAC, no H/D.

Next shot - repeat last shot.
Jul 1 2002 12:20:06:897PM1020701004Dmitri MossessianFizzle or dud - no data at all.

Next shot - repeat with no change.
Jul 1 2002 12:45:34:340PM1020701005Dmitri MossessianThe data system sould be fixed. We are not sure why we did not have
plasma last shot, but we will repeat with no changes to see that
tha data system is OK.

H/D signal is apparently fixed, the problems have been caused by
a software change between shots 1 and 2.

Plasma. Density ramps up to 5.4e19 without gas. H/D is 20%, constant
throughout the shot.

Next shot - repeat with no change. Stop ECDC between shots.
Jul 1 2002 01:03:35:870PM1020701006Dmitri MossessianPlasma. Br may be a little low. Density 5e19. H/D is 20% const

For next shot - Br offset 0.001 -. 0.0015.
Go to double null - load segment 2 from 1020621020, programmed nl to 3e19
Jul 1 2002 01:20:13:520PM1020701007Dmitri MossessianPlasma. But single null - PO mistake - the shot I loaded was a single null.
Density was lower 4e19, probably because of shorter ECDC before the shot.
H/D was 40%

Next shot - loaded segment 2 from 1020628006 - real double null now.
Program density to 3e19
Jul 1 2002 01:39:20:470PM1020701008Dmitri MossessianPlasma. Double null. Density stays at 3e19 with a lot of gas puffing.
Bruce says the walls are pumping.
H/D signal is very noisy.

For next shot - density up to 4e19, no other changes.
Jul 1 2002 02:13:03:617PM1020701009Dmitri MossessianGood plasma. Density at 4e19 as programmed.
H/D signal is noisy, ~50% average.

Next shot - no changes in PCS. ECDC between shots for 10 min.
Jul 1 2002 02:34:52:673PM1020701010Dmitri MossessianFizzle. Too much gas - 0.1 instead of 0.085 mtor F-side pressure. Probably
because of ECDC. Also, the gate valves were shut before the shot.

For next shot - prepuff from 0.28 to 0.23. No other PCS changes.
No ECDC between shots this time
Jul 1 2002 02:48:09:147PM1020701011Dmitri MossessianPlasma. Slightly lower gas puff during the shot. Density 4e19.
H/D is lower, average ~ 20%.

For next shot - repeat previous shot with ECDC between shots again.
Jul 1 2002 03:21:19:683PM1020701012Dmitri MossessianNo power shot
Jul 1 2002 03:30:57:730PM1020701013Dmitri MossessianRepeating shot 11.

No power shot
Jul 1 2002 03:41:34:137PM1020701014Dmitri MossessianRepeating shot 11.

PLasma. Looks very similar to shot 11

Next shot - go to higher density 1e20. No ECDC between shots.
Jul 1 2002 03:51:18:603PM1020701015Dmitri MossessianPlasma. PO forgot to load the higher density configuration into PCS.

Next shot - another attempt to go to 1e20.
Jul 1 2002 04:13:57:530PM1020701016Dmitri MossessianDud. Sparker did not spark.

Next shot - no change
Jul 1 2002 04:33:48:747PM1020701017Dmitri MossessianGood plasma. Density 1e20, H/D about 16%.

Next shot - no changes. ECDC between shots for 5 min.
Jul 1 2002 04:55:45:140PM1020701018Dmitri MossessianGood plasma. Same as shot 17. Density 1e20, H/D is better - about 10%.

Next shot - go back to single null. Loaded segment 2 from shot 1020701006.
Loaded density trace into segment 2 from 1020701018 (1e20)
Jul 1 2002 05:15:30:890PM1020701019Dmitri MossessianFizzle. F-side pressure gauge died.

Next shot - repeat with no change
Jul 1 2002 05:28:40:597PM1020701020Dmitri MossessianFizzle again.

Next shot - drop the prepuff 23 msec -> 20 msec
Jul 1 2002 05:44:31:090PM1020701021Dmitri MossessianFizzle again.

Next shot - lower Bz 1 mT. IC_EF4 -1330 -> -1350
Jul 1 2002 06:11:04:193PM1020701023Dmitri MossessianPlasma. Barely made it at startup. Bz too low. H/D is slightly
lower than on shot 18 - starts from 10% but goes up to ~13% only
by the end of the shot

End of run

Engineering Operator Comments
ShotTimeTypeStatusComment
110:33:20:840AMPlasmaOk
210:54:54:953AMPlasmaOk
311:34:42:670AMPlasmaOk
411:58:58:363AMPlasmaOk
512:33:10:947PMPlasmaOk
612:50:09:253PMPlasmaOk
701:08:34:500PMPlasmaOk
801:25:48:123PMPlasmaOk
901:53:52:993PMPlasmaOk
1002:18:28:687PMPlasmaOk
1102:35:25:613PMPlasmaOk
1203:03:05:950PMTestBad
1303:19:38:647PMTestBad
1403:32:08:730PMPlasmaOk
1503:48:02:520PMPlasmaOk
1604:05:59:720PMPlasmaOk
1704:25:10:843PMPlasmaOk
1804:45:00:513PMPlasmaOk
1905:06:36:970PMPlasmaOk
2005:24:25:637PMPlasmaOk
2105:38:53:410PMPlasmaOk
2205:52:25:117PMPlasmaOk
2306:04:49:137PMPlasmaOk