Alcator C-Mod Run 1021017 Information

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Miniproposals
Miniproposal:265
Date Filed: 4/7/2000
Title:CXRS Commissioning
First Author:E.C. Eisner
Session Leader:Bill Rowan (shots 1-32)

Operators
Session leader(s):Bill Rowan
Physics operator(s):Steve Wolfe
Engineering operator(s):Ed Fitzgerald,Bill Byford

Engineering Operator Run Comment
MP#265 CXRS Commissioning SL:Rowan PO:Wolf EO:Byford/Fitzgerald

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:31:350PM
Author: To Be Determined
Session Leader Summary for 1021017

Goal
Acquire CXRS spectral data in quiescent discharges to
determine limits of present diagnostic configuration. This run will
consist of many identical shots and one or two density scans. The
questions to be answered are: How far into the plasma can
measurements be made? What is the signal attenuation with increasing
plasma density? Are the Ti inferences reasonable?


CXRS
During the last few weeks, CXRS data has been acquired for various discharges.
This data is difficult to analyze because of the temporally varying background.
This experiment is intended to provide shots which do not have that impediment
so that a line shape model can be selected and so that the limits of the
measurement can be determined.
Beam-induced CXRS spectra were measured in the outer third of the plasma radius.
These signals were observed to diminish at the higher end of the density scan.
This data will be used with penetration and emission estimates to determine the
density limit for the measurement. The spectra are of sufficient quality so
that a line shape model can be developed and Ti measured.

Beam component mix
For a day prior to this experiment, the beam was operated at a high rep rate.
After the experiment, the beam component mix measurement was setup and the
component mix was measured to be [E, E/2, E/3, E/18] = [0.33,0.12,0.36,0.19]
This is an improvement since the last measurement on 10/04/02.

Beam operation
The beam required repair in the course of the run. This is unusual.
A collection of power supply faults was registered by the control program.
These would not clear. We have seen this on rare occasions in the past.
To clear them, the Budker Institute camac unit was cycled.
In the course of this, a second problem developed. A contactor would not
close. This is the same charging contactor that caused a loss of beam
operation time about two weeks ago. This time, the contactor was made
operable by cycling it manually.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:16:583PM
Author: To Be Determined
Physics Operator Summary for Thursday Oct 17, 2002

MP: 265 CXRS commissioning
SL: Rowan
PO: Wolfe
EO: Byford, Fitzgerald

The goal for this run is to acquire CXRS spectral data in
quiescent discharges to determine limits of present diagnostic
configuration. This run will consist of many identical shots
and one or two density scans. The questions to be answered
are: How far into the plasma can measurements be made?
What is the signal attenuation with increasing plasma density?
Is Ti measurement reasonable?

Engineering Setup
-----------------
Power Systems as on 1021011001

Overnight ECDC in D2 at 2e-4 torr off by 7:00AM

Run to begin at 9:00 AM
Gas setup:

B-Top 6 psi D2 Hybrid Enabled (PG4)
B-side lower 1 psi Ar Hybrid Enabled (PG1)
B-side upper 10 psi D2 Hybrid DISABLED (PG2, for ECDC)
C-Side 30 psi D2 Hybrid Enabled (PG3)
J-Bottom as is, Hybrid DISABLED

Enable the following gate valves, assuming no vacuum problems:
ECE,VUV,DNB

RF Setup: None - Ohmic only run

PCS Setup
----------

Import seg2 from 1021011001 and change Itf from -153kA to -147.4kA (nominal
5.3T) change nl04 from 8e19 to 6e19. I took seg1 from the last shot from
Wednesday, and lowered pg4 to 32msec.

I also spent some time fixing up the predictors so they no longer give invalid
row message when you try to look at them in EDIT_WIRE|EDIT . This required
recalculating the predictors on all wires except RCUR, ZCUR, BR_0 and IC_EF4U;
the former I had done yesterday, and the others didn't need it, presumably
because those get exercised every day.

I believe that these predictors got somehow corrupted by an inadvertent call
to the ALGs button on segment #1. This seems to have happened once before,
on 1020531013. I had also noticed that using the segment ALGS button caused
problems. Physops should avoid the use of this "feature" until the bugs are
identified and fixed. See notes in logbook for yesterday and today for more
info.

Results:
--------

A boring run, from the Physop's point of view. The Session Leader seemed happy
enough though. We spent most of the day at the initial density of 6e19, then
went up to 8e19 (#21), 1e20(#22-24,26-27), back down to 8e19 (#28), and down
to 5e19 (#29-3

Startup was pretty robust today, despite the fact that I couldn't resist
tweaking at it. I tried using Ian's trick of varying the drawn RCUR point at
0.001 sec. Over several shots I moved this from .69 to .66m, but I'm not
convinced it actually did anything. The major control knob continued to be the
gas (PG4). I started at 32msec, worked it up as far as 39, then later in the
run came back down as far as 30, and then as we lowered the density went back
up as far as 37msec on the last shot. The effect on outside bounces and
associated runaways was always in the expected direction, though not always as
large as I expected for a given change.

We had one power supply dud (#9, no TF) and one disruption caused by a TCI
feedback failure (#25); that shot seems to have fueled to close to the
Greenwald limit. We had one fizzle (#23) due to not lowering the gas enough,
leading to a fatal snuff on the inside.

The beam behaved reasonably well, although we did lose about an hour after a
problem with the control signals and a contactor.

The data system was well behaved today, with only one shot held up a few
minutes to clear a stuck job.

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

32 shots. 30 plasmas. 1 fizzles. 1 duds (no TF)


Session Leader Comments
Oct 17 2002 08:00:07:197AMBill Rowan
The goal for this run is to acquire CXRS spectral data in
quiescent discharges to determine limits of present diagnostic
configuration. This run will consist of many identical shots
and one or two density scans. The questions to be answered
are: How far into the plasma can measurements be made?
What is the signal attenuation with increasing plasma density?
Is Ti measurement reasonable?
Oct 17 2002 09:15:10:217AM1021017001Bill Rowan001. Beam is at approximately 50 kV. 50 ms.
Oct 17 2002 09:21:59:627AM1021017002Bill Rowan002. 30 ms beam. Otherwise, okay.
Oct 17 2002 09:32:29:763AM1021017003Bill Rowan003. Beam did not fire on that shot.
Interlock failed to clear.
Oct 17 2002 09:52:05:037AM1021017004Bill Rowan004. Beam was 50 ms. Max accelerated current was 4A
Oct 17 2002 10:47:13:717AM1021017004Bill RowanDelay due to beam power supply problem.
Contactor for charging supply would not close.
Cycled contactor by hand and then it began
to work.
Oct 17 2002 11:01:15:283AM1021017005Bill Rowan005. Beam was fired late. The pulse length was approximately 10 ms.
Oct 17 2002 11:08:03:897AM1021017006Bill Rowan006. Beam firec properly. CXRS signals.
Oct 17 2002 11:37:54:057AM1021017008Bill Rowan008. Beam faulted.
Oct 17 2002 01:31:50:237PM1021017016Bill Rowan016. Beam faulted. 15 ms.
CXRS data not usable on this shot. Good measurment of
ambient emission. Useful for analysis of other data.
Oct 17 2002 01:39:29:130PM1021017017Bill Rowan017. Beam faulted. 15 ms beam.
Oct 17 2002 02:11:31:047PM1021017018Bill Rowan018. 50 ms beam. Good current.
Good CXRS signal
Oct 17 2002 02:10:10:103PM1021017019Bill Rowan019. Beam fault. 12 ms.
Not of much use.
Oct 17 2002 02:25:26:600PM1021017020Bill Rowan020. 50 ms beam. Adequate current.
Good cxrs signal.

Next shot. Begin a density scan
Oct 17 2002 02:50:38:337PM1021017021Bill Rowan021. 50 ms beam. Good current.
nel04 = 8e19
Cxrs signal getting smaller.
Oct 17 2002 03:03:00:730PM1021017022Bill Rowan022. 50 ms beam. good current
nel04 = 1.1e+20
Oct 17 2002 03:02:07:963PM1021017023Bill Rowan023. 50 ms beam. good current
fizzle
Oct 17 2002 03:17:20:647PM1021017024Bill Rowan024. Good beam. Good plasma.
Oct 17 2002 03:30:09:587PM1021017025Bill Rowan025. Good beam. Plasma density was uncontrolled.
Not a useful shot. Detector saturated.
Oct 17 2002 03:56:31:547PM1021017026Bill Rowan026. Good beam. Plasma density okay

Oct 17 2002 04:04:30:520PM1021017027Bill Rowan027. Good beam. Plasma density okay

Next shot. Reduce density.

Oct 17 2002 04:19:22:517PM1021017028Bill Rowan028. good beam. Plasma at approximately 8e19 nl
Good cxrs signal.
Oct 17 2002 04:30:32:903PM1021017029Bill Rowan029. Plasma. nel=5.5e+19
Very short beam. Must try again.
Oct 17 2002 04:45:02:880PM1021017030Bill Rowan030. Good beam. Plasma at approximately 5e+19.
Good cxrs, of course -- low density.

Oct 17 2002 04:57:04:210PM1021017031Bill Rowan031. Good beam at 0.5s. Plasma at approximately 5e+19.
Very large signal, but ambient emission was changing rapidly
as well.


Physics Operator Comments
Oct 17 2002 07:17:40:447AMSteve WolfeSetting up for Thursday 1021017 run:
Import seg2 from 1021011001 and
change Itf from -153kA to -147.4kA (nominal 5.3T)
change nl04 from 8e19 to 6e19
Seg 1: take setup from last shot Wed and:
call alg in all wires except RCUR, ZCUR, BR_0 and IC_EF4U, which didn't need it.
the others all gave invalid predictor warning on trying to edit predictor, all
had alg_version of 3-FEB-1993 or DUMMY, as on the CLEAR preds in rows 1 and 3
Note that the current versions are :
fluxihh : "2-Oct-02 Radial posi...
filament: "01-JUN-1993 19:15:00"
custom: "today"
` vacuum: "1-FEB-1993 13:01:26"
rogowski: "9-FEB-1993 13:01:26"
pre-puff pg4 from 35 to 32msec
Load/clean
Load at 17-Oct-2002 07:05:37.00
Do a coldstart (from claret)
All matrices respond.
hloader log ok.
Oct 17 2002 07:50:34:703AMSteve WolfeGot a clue on how the seg1 on 1021008008 - 1021016025.

Looking at the log from 1020531, where the previous series of "funny" alg_version
values originated on shot 13, I see that Ian has a note about having tried to edit the
"Rcur controller" and then talks about using the algs button:
----------------------------------------------------------------------------
1020531012 hutch PHYSICS_OPERATOR May 31 2002 3:09:14:510PM
. . . . . . . . . . . . . . . . . . . .
Called the Rcur controller. Initially when I tried to edit it, it said
I could not because bp26 was wrong. Then after calling it had bp26_bc and
could be displayed through edit.

Then hit the algs button in segment 1. It seemed to call all the algorithms.
There were a few where the scale factor did not satisfy the criterion for
all the values, but I ignored that and just hit ok.
Load.

Call the algorithms for segments 2-4. All ok except for the NL04 factor
which I just oked anyway.
Load/clean.
------------------------------------------------------------------------------

I have previously noted anomalous behavior when using the segment-wide call_algs
button. I suspect that Bill accidentally hit the seg1 call_algs button, and it
somehow generated these screwy alg_version values and did something that left the
rows in an "invalid" state. I don't understand how the offset=3600. value survived,
but maybe that is related to the bug in call_algs?

The last shot in the older sequence seems to have been 1020606012. There is no
specific information in the logbook, but it looks like that was the shot on which
Bob updated the calibration of the replacement BTOR signal (when the real BTOR
was MIA), and it may be that Irby, who was physop that day, recalculated predictors,
which would have removed the anomaly.
Oct 17 2002 09:14:48:217AM1021017001Steve WolfeShot#1: Startup like shot 1021016032 except for pg4 at 32msec instead of 35
Seg 2 like 1021011001 with nl4 to 6e19 and itf to -150000 (not 147400, as claimed above)

plasma, full length.
Some current rise hesitation, no bounce, Br a little negative, so is Bz[0.0]
Pressure is .06 to .07mTorr; plenum pressure is 6.3psi today

One small injection at .85sec; H/D=.05
No ece signal; No Thomson.

next shot: repeat, unless Bill wants something changed
Oct 17 2002 09:31:43:137AM1021017002Steve WolfeShot#2: repeat
plasma, full length.
some indications of bouncing on the Halpha, slightly faster current rise,some hards

TS on this shot, gpc1 still missing
Sam will check pre-amps on gpc1- one amplifier was off
next shot: repeat
Oct 17 2002 09:35:38:883AM1021017003Steve WolfeShot#3: repeat
plasma, full length.
Startup is looking bouncier.
gpc1 is back, not many hards this time

next shot: rcur[0.001] from .69 to .68
Oct 17 2002 09:47:00:617AM1021017004Steve WolfeShot#4: rcur[0.001] from .69 to .68

plasma, full length, bd slightly late 7msec
Br is down close to -.001 at t=0. No obvious bounce, no hards

next shot: repeat
Oct 17 2002 10:56:28:490AM1021017005Steve WolfeShot#5: repeat after a cell access for beam (slightly over an hour)
plasma full length.
bouncy startup again, current turns around. bd back at 5.4msec, br0=-.001

next shot: raise br0 by .5mT
Oct 17 2002 11:07:32:880AM1021017006Steve WolfeShot#6: raise br0 from .0015 to .0020, expect pressure to come up by itself
plasma, full length
Another bouncer, breakdown back at 7msec; Br did come up

next shot: increase pg4
Oct 17 2002 11:20:52:633AM1021017007Steve WolfeShot#7: increase pg4 from 32 to 34ms
plasma full length
Still bounced. bd at 6ms, current rise still reversing.

next shot: another rcur[.001] tweak
Oct 17 2002 11:25:36:363AM1021017007Steve WolfeShot#7: increase pg4 from 32 to 34ms
plasma full length
Still bounced. bd at 6ms, current rise still reversing.
On shots 6 and 7 I've been getting a message that bp22jk does not begin
near zero by 45mT. This is true. I'm wondering whether Ian's Br predictor in the tree,
which uses the processed bp's without baseline subtraction, may be getting
pulled off by the offsets. This signal does not go to the hybrid,
and the actual hybrid predictor for Br0 doesn't use the bp's at all.

next shot: another rcur[.001] tweak
Oct 17 2002 11:34:21:467AM1021017008Steve WolfeShot#8: another rcur[.001] tweak from .68 to .67
plasma, full length
still bounces, but later, around 15msec, less turnaround.
I don't know whether the rcur[.001] is affecting it or the
gas is just evolving.

next shot: tweak it again
Oct 17 2002 11:47:37:033AM1021017009Steve WolfeShot#9: another rcur[.001] tweak from .67 to .66

dud - no tf.
Oct 17 2002 12:03:20:607PM1021017010Steve WolfeShot#10: rcur[.001] from .67 to .66
plasma full length
Still bounces, this time earlier. Less turnaround though.
Still lots of hards.

next shot: raise pg4
Oct 17 2002 12:19:05:820PM1021017011Steve WolfeShot#11: raise pg4 from 34 to 36msec
plasma full length
still bouncing, current turned around again this time.
looked like hards on the tv.

next shot: more gas igor
Oct 17 2002 12:37:55:340PM1021017012Steve WolfeShot#12: raise pg4 from 36 to 39msec!
plasama full length
no bounce. startup looks good.
pressure is still only ~.08 mTorr or so; Btop piezo may be getting sticky.

next shot: no changes
Oct 17 2002 12:48:55:353PM1021017013Steve WolfeShot#13: no changes
plasma full length
No bounce, slightly faster current rise.

next shot: repeat
Oct 17 2002 01:02:56:783PM1021017014Steve WolfeShot#14:repeat
plasma full length
small injection at .13 sec
maybe a small early bounce, but no hards

next shot: repeat
Oct 17 2002 01:15:14:253PM1021017015Steve WolfeShot#15:repeat
plasma full length
no bounce

next shot: repeat
Oct 17 2002 01:28:20:587PM1021017016Steve WolfeShot#16: repeat
plasma full length

next shot:repeat
Oct 17 2002 01:40:09:337PM1021017017Steve WolfeShot#17: repeat
plasma full length, startup still ok

next shot: repeat
Oct 17 2002 01:57:11:070PM1021017018Steve WolfeShot#18: repeat
plasma full length
startup still ok

next shot: repeat - Bill says one more good beam shot at this density
Oct 17 2002 02:10:25:917PM1021017019Steve WolfeShot#19: repeat - Bill says one more good beam shot at this density
plasma full length, breakdown a little late 7msec, br drifted a bit more positive

next shot: Bill says we'll need another one.
Oct 17 2002 02:23:56:423PM1021017020Steve WolfeShot#20: repeat - Bill says one more good beam shot at this density
plasma full length, bd still around 7msec, br back where it was.

next shot: raise density to 8e19
Oct 17 2002 02:36:26:863PM1021017021Steve WolfeShot#21: raise nl04 from 6 to 8e19

plasma full length, nl4=8.2e19, bd still around 7msec

next shot: raise density to 1e20
Oct 17 2002 02:51:00:887PM1021017022Steve WolfeShot#22: raise nl04 from 8e19 to 1e20

plasma to 1.96sec,nl4=1.05e20
bd back at 5.5msec again. This one hesitated, and swung in a little bit.

next shot: repeat, drop pg4 by 2msec
Oct 17 2002 03:03:58:233PM1021017023Steve WolfeShot#23: nl04 at 1e20, seq1 pg4 from 39 to 37msec

fizzle. Should have dropped it more.

next shot: pg4 to 34msec
Oct 17 2002 03:16:26:987PM1021017024Steve WolfeShot#24: nl04 at 1e20, pg4 from 37 to 34msec

plasma to 1.98sec, skight hesitation, no bounce
nl4 1.0-1.1e20

next shot: repeat this density once more
Oct 17 2002 03:34:11:597PM1021017025Steve WolfeShot#25: pg4 from 34 to 32msec

plasma disrupted at 1.30sec, tci feedback went negative on me,
so gas was full on for almost the whole pulse.
density got to nl4>3e20
startup is looking like it was close to snuffing, despite reducing the puff;
pressure was down to .07mTorr
Irby will need a cell access to check on a HeNe

next shot: No changes, and hope it goes
Oct 17 2002 03:50:33:170PM1021017026Steve WolfeShot#26: No changes, and hope it goes
plasma full length
nearly snuffed, swung back in but made it.

next shot: repeat the density, lower pg4 a bit more
Oct 17 2002 04:18:30:513PM1021017028Steve WolfeShot#28: nl04 to 8e19

plasma full length, nl4~8.2e19, but it looks like it has about
five little L-H-L transitions in flattop!
startup looks like previous

next shot: 5e19
Oct 17 2002 04:32:25:113PM1021017029Steve WolfeShot#29: nl04 to 5e19, drop seg2 pg3 maint level from ~20 to ~15

plasma full length, startup similar, less hesitation
nl4=5.4e19, Bill wants it lower.

next shot: demand to 4.5e19
Oct 17 2002 04:44:10:770PM1021017030Steve WolfeShot#30: nl04 demand to 4.5e19, redraw pg3 out to 1.5sec

plasma full length, but looks like some runaways.
It bounced early in startup, time to start raising pg4 again.
nl4=4.8e19

next shot: repeat this density
Oct 17 2002 04:55:45:207PM1021017031Steve WolfeShot#31: pg4 from 30 to 34msec, same nl4 program

plasma full length, still had runaways. Another early bounce.

next shot: raise pg4 again
Oct 17 2002 05:08:29:037PM1021017032Steve WolfeShot#32: pg4 from 34msec to 37msec, same nl4 program

plasma, full length, still runaways.

That's all folks.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:02:16:560AMPlasmaOk
209:16:12:017AMPlasmaOk
309:29:01:100AMPlasmaOk
409:41:45:540AMPlasmaOk
510:51:20:663AMPlasmaOk
611:04:03:870AMPlasmaOk
711:17:29:827AMPlasmaOk
811:30:15:627AMPlasmaOk
911:45:40:887AMPlasmaBadTF did not go
1011:58:37:953AMPlasmaOk
1112:15:55:203PMPlasmaOk
1212:28:29:720PMPlasmaOk
1312:43:15:933PMPlasmaOk
1412:56:24:093PMPlasmaOk
1501:09:38:177PMPlasmaOk
1601:22:57:133PMPlasmaOk
1701:36:10:137PMPlasmaOk
1801:54:03:217PMPlasmaOk
1902:07:09:487PMPlasmaOk
2002:20:03:913PMPlasmaOk
2102:32:53:010PMPlasmaOk
2202:45:48:467PMPlasmaOk
2302:58:41:953PMPlasmaOk
2403:11:40:677PMPlasmaOk
2503:24:42:430PMPlasmaOk
2603:46:45:100PMPlasmaOk
2704:00:05:120PMPlasmaOk
2804:13:24:763PMPlasmaOk
2904:26:37:190PMPlasmaOk
3004:39:41:053PMPlasmaOk
3104:52:40:057PMPlasmaOk
3205:06:02:263PMPlasmaOk