Alcator C-Mod Run 1010713 Information

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Miniproposals
Miniproposal:281
Date Filed: 9/7/2000
Title:Imaging of Edge Turbulence in Alcator C-Mod
First Author:Jim Terry
Session Leader:Jim Terry (shots 1-21)
Miniproposal:289a
Date Filed: 5/2/2001
Title:Investigations of Double Transport Barrier Plasmas
First Author:John Rice
Session Leader:John Rice (shots 1-22)

Operators
Session leader(s):Jim Terry,John Rice
Physics operator(s):Steve Wolfe
Engineering operator(s):Ed Fitzgerald

Engineering Operator Run Comment
RF antenna conditioning,MP289A,MP259,MP137,MP233SL:?,PO:Wolfe EO:Fitzger

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:37:13:833PM
Author: To Be Determined
Physics Operator Summary for Friday, July 13,2001

Boronization Recovery and MP???
PO: Wolfe
EO: Fitzgerald,
SL: ?

Run Plan and ENGINEERING SETUP:
---------------------------------
Boronization overnight, followed by 2 hours ECDC in He
followed by 1hour ECDC in D2

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

Power systems the same as for shot 1010712009

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 6 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:

Recovery from boronization, RF antenna conditioning
If the RF is far enough along, we will begin MP289A ITB studies.
In the event of RF problems, fall back MP's include:
MP259 MSE calibration (beam into gas with field) Yuh
MP137 L-H-L transitions Hubbard
MP233 Density Limits [g],laBombard
Piggybacking by MP281 Edge Turbulence Imaging is expected on any
of the above except MP259.

Results:
--------

The vessel was boronized last night with about 2000 Angstroms of boron,
followed by 2 hours of ECDC in helium at 5e-5 Torr, and 1 hour of ECDC in D2
at 2e-4 Torr.

First shot (#2) was loaded from 1010712010 (800kA, 7e19, 5.4T)
Minor shape tweaks were made during the course of the run, to
increase the upper triangularity and to decrease the outer gap
to 1cm, in order to aid the RF loading. The latter change didn't
seem to matter, and was left in place.

Machine recovery was good, and the H/D ratio was fair, starting the day below
5%, but increasing to 7-12% during H-modes with RF. We had only one fizzle
(#5), and all shots but one ran through rampdown. The one disruption, #7, was
induced by a J-antenna injection. On this shot the circuit that forces FMIT#3
and 4 to shut down together when either sees a fault had been intentionally
disabled, and the two halves of the antenna were running independently
(exclusively), leading to the injection. After #7, the simultaneous faulting
circuit was reenabled.

The RF conditioning was slower. E came up quickly to 1MW, and wasn't
pushed further. By the end of the run, J ran at 1MW for .6sec into
L-mode, but tripped during H-mode. H-modes were routinely obtained with E at
1MW, although the timing of the L-H transition moved around some, indicating
the power was near threshold. The last shot (#22) had an H-mode with J alone
at 1MW, after a long L-mode phase.

D had problems all day. It was first thought that the antenna needed vacuum
conditioning, but it came quickly up to >35kV in vacuum, and the subsequent
perfomance into plasma was no better. The symptom was repetitive phase balance
faults when the power went above 100kW. These are tentatively diagnosed, late
in the run, as being due to a noisy demodulator on a current probe that was
being used for phase balance fault detection. On the spot attempts to remedy
this by using the voltage phase instead, were not successful, and the problem
remains to be dealt with before the next run.

Stew Zweben's ultrafast camera was imaging edge turbulence with a deuterium
gas puff, and some excellent videos were produced. The optimum framing rate
seems to be about 8usec, which allows one to follow a blob moving around for a
typical lifetime. This observation is consistent with the observed
auto-correlation time from probe measurements.

The DNB was operating into plasma, beginning with shot#4, and they got some
data. My impression is that only about half of their attempts to put beam
into plasma were successful today.

The first shot of the day had to be abandoned (no power cycle) because of a
I^2t fault in INIT. IGOR had to be bypassed to go to INIT on the next shot, in
order to force a state transition, but was ok thereafter. There were no other
camac, computer, or engineering problems all day. The OH2L coax resistance was
running a bit high, around 1.2uOhms and up to 1.5uOhm on at least one
shot. This will need to be monitored.

ECDC will be run all weekend, and the vessel bake raised to 60C. Hopefully,
this will help with the H/D.

Scorecard:
----------

"Tests" 1
Duds 0
Fizzles 1
Plasmas 20
------ --
Shots 22


Session Leader Comments

Physics Operator Comments
Jul 13 2001 07:11:25:723AMSteve Wolfecoldstart at 07:10. All matrices respond ok.
Jul 13 2001 07:13:44:057AMSteve WolfeRun Plan and ENGINEERING SETUP FOR 1010713:

Boronization Recovery and MP???
SL: ?
PO: wolfe

Boronization overnight, followed by 2 hours ECDC in He
followed by 1hour ECDC in D2

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

Power systems the same as for shot 1010712009

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 6 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:

Recovery from boronization, RF antenna conditioning
If the RF is far enough along, we will begin MP289A ITB studies.
In the event of RF problems, fall back MP's include:
MP259 MSE calibration (beam into gas with field) Yuh
MP137 L-H-L transitions Hubbard
MP233 Density Limits [g],laBombard
Piggybacking by MP281 Edge Turbulence Imaging is expected on any
of the above except MP259.
Jul 13 2001 07:48:03:767AMSteve WolfeReload from 1010712010 (last shot from yesterday).
If and when we go to the double barrier experiment,
I'll just copy the tf waveform from 1001220016 s2;
that shot had the old clearin and rcur offsets, and
used nl_zmeter feedback. I don't want to propagate
any of those.
Jul 13 2001 09:09:39:373AM1010713001Steve Wolfeshot#1: No power cycle due to I^2t fault in INIT
Jul 13 2001 09:42:55:660AM1010713002Steve Wolfeshot#2: plasma, full length
breakdown pressure looks low ~.045

got 700kW from E, faulting from D and J.
density rises during RF. Brief h-mode at 0.87sec
A few injections. H-D between 4 and 5%

ECDC for 5minutes between shots.
Jul 13 2001 10:03:16:080AM1010713003Steve Wolfeshot#3: Leave gas alone, see if pressure is up after a shot+ECDC
start init at 3.7e-6 gage.
plasma, full length
p0 up to .065 this time.
density rises to 1e20 during RF (still just E staying on).
h/d 4.5% again.

Run ecdc 5 minutes between shots (from now on)

Jul 13 2001 10:20:43:170AM1010713004Steve Wolfeshot#4: dnb will open and shoot this time (.7sec), may affect pre-fill.
start init at 3e-6Torr

plasma, full length. Brief H-mode at ~.88sec
One early injection. E has one dropout at ~1sec, recovers
D and J still faulting.
breakdown pressure ~.06mTorr, breakdown a little late. Leave it alone for now.
Jul 13 2001 10:44:11:847AM1010713005Steve Wolfeshot#5: fizzle. late breakdown 9.5msec.
I don't think it was gas, which was the same as last time.
drop br .5mT, ef4 by 10amps
Jul 13 2001 11:10:18:997AM1010713006Steve Wolfeshot#6:BR0 from .0015->.001, EF4 -1280->-1290, PG4 20->22msec
RF had a cell access to work on D and J control cabinets

plasma, full length, couple of short h-modes
breakdown back to 6msec, p0 stil around .065
Got the Br change, Bz not much different.
E at 1MW, J stays on for ~25msec at 250kW. D still faulting.
H/D hanging in at 5-6%

next shot: increase pg4 another 2msec
Jul 13 2001 11:35:24:160AM1010713007Steve Wolfeshot#7: increase pg4 another 2msec

disruption at 0.6sec; J ran half off (they had the simultaneous kill jumped out).
breakdown time was good (5.5msec), pressure still on the low side.

next shot: sim kill back in on J, they found out what they needed to.
I'm tempted to lower the fill post-disruption, but it's so low anyway I'll leave it.
Jul 13 2001 11:50:56:933AM1010713008Steve Wolfeshot#8: plasma, full length. H-mode from 1-1.5sec

No ecdc this time, Steve wants to vacuum condition D.
Jul 13 2001 12:14:45:093PM1010713009Steve Wolfeshot#9: plasma full length
h-mode 1.0 - 1.4sec
injection at .56 (jport?) multiple faults on J-port.
E at 1MW, drops out at 1.4sec then comes back on
H/D now up to 7-8%
Jul 13 2001 12:32:02:200PM1010713010Steve Wolfeshot#10: D is vacuum conditioned, will try again into plasma.
disruption at 1.18sec
D tried a little longerm but couldn't hold it.
H/D still ~7%

next shot: try again.
Jul 13 2001 12:42:53:530PM1010713011Steve Wolfeshot#11: plasma full length, eda-ish h-mode from 1-1.5sec
J stays on this time at .15MW each
E looks good at 1MW, D still faulting

back to ECDC between shots (5min)
Jul 13 2001 01:09:54:727PM1010713012Steve Wolfeshot#12: plasma, full length. H-mode, not great.
J ramps to ~.5MW, E at 1MW a little ragged
D still not happy
H/D starts at 6%, goes up to 1o% dring the H-mode.



Jul 13 2001 01:38:50:037PM1010713013Steve Wolfeshot#13: plasma full length, h-mode from 1-1.5
A little more from J this time.
D doesn't seem to want to go over 100kW

next shot: move rxu from +.005 to -.005 to increase deltau
Jul 13 2001 02:00:15:210PM1010713014Steve Wolfeshot#14: move rxu from +.005 to -.005 to increase deltau
plasma, full length. Hmode from .94 to 1.5
upper triangularity did increase, still not flat.
J close to .7MW, E still at 1, D still struggling
H/D still rising to 10% in H-mode

next shot: tweak rxu to flatten the triangularity.
Jul 13 2001 02:19:03:660PM1010713015Steve Wolfeshot#15: tweak rxu to flatten the triangularity.
Make outer gap smaller, aim for 1cm; rcur from .6585 to .661

plasma, full length. H-mode from .87 to 1.25
gap is at 1cm between .5 and 1, but shrinks to .6 by 1.5
J-port close to 1MW, D still struggling, E ok at 1

next shot: increase clearin after 1sec
Jul 13 2001 02:49:20:847PM1010713016Steve Wolfeshot#16: increase clearin after 1sec,
delay the step in integral gain to .55 (after crossover)

plasma full length, hmode from .9 to 1.5
gaps are flatter. J didn't like that, pretty much just E this time
CLEARIN is showing a positive error until about 1sec, and I've drawn
a non-constant value to compensate.
They had tried to tune J for the H-mode, and it wouldn't stay on in L-mode.

Steve says the phase balance signal is depending on a weak signal.
Cell access to deal with it.
Jul 13 2001 03:16:40:420PM1010713017Steve Wolfeshot#17: Try again, no PCS changes
plasma full length, h-mode from .6 to 1.3s
looks like a bart-mode
D makes it to .3MW but still faults
J faults at .4, E comes on at .5sec and stays on.
A few small injections.
H/D over 10% for much of the shot

next shot: rf will tweak, I won't
Jul 13 2001 03:32:38:023PM1010713018Steve Wolfeshot#18: No PCS changes.
plasma, full length. H-mode from .9-1.5sec
E on at .5sec, 0.9MW, D still faulting, J otl
Jul 13 2001 03:50:51:363PM1010713019Steve Wolfeshot#19 No PCS changes.
plasma, full length, no Hmode. E was turned off
J had lots of short faults, and D still looks the same.
Jul 13 2001 04:20:23:423PM1010713020Steve Wolfeshot#20: J tune back where it worked before.
D may be getting screwed up by a noisy demodulator on a current probe
plasma full length, L-mode. J ramped to 1.5MW before tripping at .68sec.
D looks just the same. Either the Jpulse is too short or heats too
far off axis to get into H-mode on its own?

Rejean will do a cell access to change out the questionable demodulator on D
Jul 13 2001 04:45:20:790PM1010713021Steve Wolfeshot#21: plasma, full length. Looks just like 20.
Another cell access to flip polarity - now using the voltage phase
instead of the current phase.
H/D around 6-7%

Engineering Operator Comments
ShotTimeTypeStatusComment
109:08:32:233AMPlasmaBadI^2T fault after Init, power shot aborted
209:31:35:393AMPlasmaOk
309:52:05:267AMPlasmaOk
410:13:52:350AMPlasmaOk
510:35:02:770AMPlasmaOk
610:58:53:090AMPlasmaOk
711:20:55:810AMPlasmaOk
811:42:35:013AMPlasmaOk
912:03:23:967PMPlasmaOk
1012:21:49:043PMPlasmaOk
1112:36:15:940PMPlasmaOk
1212:58:39:037PMPlasmaOk
1301:22:12:357PMPlasmaOk
1401:46:05:627PMPlasmaOk
1502:08:51:893PMPlasmaOk
1602:31:32:040PMPlasmaOk
1703:00:17:443PMPlasmaOk
1803:21:40:553PMPlasmaOk
1903:43:10:353PMPlasmaOk
2004:07:10:420PMPlasmaOk
2104:33:58:527PMPlasmaOk
2204:56:52:623PMPlasmaOk