Alcator C-Mod Run 970527 Information

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Miniproposals
Miniproposal:170a
Date Filed: 5/13/1997
Title:Restart Operation: May 1997
First Author:Robert Granetz
Session Leader: Unknown (shots 1-54)

Operators
Session leader(s): Unknown
Physics operator(s):Steve Wolfe
Engineering operator(s):Frank Silva,Vinny Bertolino

Engineering Operator Run Comment
MP170A Wolfe/Silva, Bertolino

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:36:57:300PM
Author: To Be Determined
Physop Summary for 970527

MP 170A: Restart
PO: wolfe
EO: Silva,Bertolino,Silva

The object was to try to get more reproducible startups and provide target
plasmas for diagnostic alignment and, if possible, RF conditioning. All shots
were run with hybrid TF control, breaking down at 5.3T and ramping down to
about 4T.

This was a reasonably successful run, on the scale of what we have been
getting this month. We ended up with 27 useable plasmas, out of 53 attempts
and one test shot. Since the nominal standard for physics runs is 25 useable
plasmas, we could claim we are ready to run from that standpoint, although
<60% startup reliability clearly leaves lots of room for improvement. There
was one extended cell access (50 minutes) in the middle of a series of
successful shots, so we might have gotten more plasmas if we kept at it.

HIREX was successful in cross-calibrating channels and produced a Ti
profile. Pitcher and LaBombard puffed trace He with the NINJA system and
observed the spectrum on their spectrometer looking at the AB limiter. Bob
Granetz got his inner cylinder flux signals working, for the lower set. Rejean
and the UMd group were both reporting values for H/(H+D) (Rejean around 25%
and Weaver around 15%). Yuichi and company got some amount of power out of
transmitter 3; the RF net power trace was reading 300kW, but Yuichi warned
that might not be correct.

The CII signals were lower all day, mostly in the .004 to .006 range. Weekend
ECDC apparently had a beneficial effect.

The dud frequency was way down, but not yet zero. It is unclear whether the
use of the straight-in viewing IGT gauge is helping with pre-ionization or
not. The x-point Thomson system was not firing today.

Shot 1 was the usual Tuesday test. Plasma attempts started with shot 2.

I started with a load of 970523019, the last successful shot from Friday; I
changed this to have only one Argon puff, and copied the tf trace from segment
2 to segment 1 so the two would match. Note that I left the TF invert at 1.2
seconds on the engineering setup, overriding the hybrid program which lasts to
1.4. The first 7 tries (#2-8) were fizzles, although several tried to go and
actually got to greater than 60kA. The tweak that got a plasma (shot 9) was a
10Amp positive increment on IC_EF4, to get more Bz in early; I had also
tweaked the seg 1 RCUR offset.

Shots 10 and 11 fizzled, on shot 12 I made a small change to IC_ef4 and got a
full plasma (to 1.63 sec, longest of the day). Snipes identified shot 12 as
having a dithering H-mode. shot 13 was similar to 12, but with an Argon puff
and 150msec shorter.

Shot 14-30 were a series of fizzles (and 1 dud); some of the fizzles actually
reached 80kA. These were clearly being thrown away somewhere, as had some of
the initial sequence. I believe these were going vertically, but static Br
offset tweaks did not help.

Shot 21 was a reload of shot 9, and gave another good plasma. From this point
on there were essentially no changes to startup. Series of plasmas were
interlaced with a few fizzle-dud sequences, but the best technique seemed to
be to wait them out. The last 11 shots in a row were all good plasmas.

Shot 35 was a short, unexplained disruption.

From shot 41 on, the outer gap was reduced to 12mm so Granetz would get more
of the edge on the high-spatial resolution xray array.

I made some progress in lengthening the shot in rampdown, although it never
got back to the pre-argon length. It should be a little more robust with the
final settings (shot 54). It might also be useful to try ramping CLEARIN
negative more quickly.

Scorecard:
---------
Tests 1
Duds 6 (1 power supply fault)
Fizzles 19 (including some with 50 < Ip < 100kA)
Plasmas 28 (27 useable, into ramp-down)
------ --
Total 54

Session Leader Comments

Physics Operator Comments
May 27 1997 07:47:31:130AMSteve WolfeRun 970527 setup
07:02 Coldstart ran ok.
Terryvision seems to have a filter installed. Can't see ECDC.
Start from 970523019 (last successful shot), but with only
one Argon pulse.

First shot will be Tuesday test.
May 27 1997 07:50:43:150AM970527001Steve WolfeShot 1: Tuesday OH test.

Supplies went. looks ok
May 27 1997 08:07:38:010AM970527002Steve WolfeShot 2: Load from 970523019 with the following changes:
Remove all but one Argon puff, shorten to 25msec
Copy seg 2 TF pulse to seg1.
Load at 27-May-1997 07:53:56.00
Note that TF is inverting at 1.2, although program runs to 1.4.
On last shot Friday the TF did not go; we want to see if it is working now.
base=5e-7

fizzle. Could see it on tv.
bd at 6msec; CII at .011
EF4's not fully cold. Br a little negative.
It almost went anyway.

May 27 1997 08:24:18:360AM970527003Steve WolfeShot 3: Repeat.
Wait for EF4's to get full cold.
There was a small teflon burst on shot 2.

fizzle. got to 40kA.
CII signal is at .004 early, then it smashes.
Bz comes in late
May 27 1997 08:32:42:900AM970527004Steve WolfeShot 4: Drop pre-puff from 20msec to 18msec
another fizzle.
bd a little later, 7msec.
visible on ECE ch 1-8; looks like it's moving out.
Br perhaps a little positive now.


May 27 1997 08:41:37:550AM970527005Steve WolfeShot 5: Br offset from .0065 to .006
RCUR offset from 6850 to 6900.
fizzle. It tried twice. seems to move out, then restrikes and moves in.
Br is now negative.
May 27 1997 08:49:12:610AM970527006Steve WolfeShot 6: Br offset back from .006 to .0065
fizzle. This is getting monotonous.
GOt to 60kA this time, getting closer.

I'm not sure whether I'm losing it outside or up-down. Try another tweak on Br.
May 27 1997 08:55:09:990AM970527007Steve WolfeShot 7: Br offset from .0065 to .007
another fizzle, looked weaker and neat top?
only 40kA. later bd (8msec)
can't see it on ece this time.


May 27 1997 09:02:52:410AM970527008Steve WolfeShot 8: Br offset back to .0065 from .007
RCUR offset to 6950 from 6900.

fizzle again. back to 60ka, losing it at 20msec.
bd at 6.2msec,
plasma is still outside.
May 27 1997 09:14:37:880AM970527009Steve WolfeShot 9: EF4 from -1310 to -1300
plasma to 1.54 sec,
fast current rise, at 150kA by 30msec
we now have significant early bz.
density is a little ratty, but not bad.
gaps look ok.

May 27 1997 09:23:19:760AM970527010Steve WolfeShot 10: No changes.
Mike in power room to turn on transmitters.
base=1.3e-6
fizzle. Can't get two in a row.
very late bd (11msec)
null looks totally different, no early Bz, slight negative Br.
May 27 1997 09:37:18:760AM970527011Steve WolfeShot 11: No changes.
base=8e-7
fizzle. 45kA; bd at 8msec
field still comes in late.
nothing on ece this time.

May 27 1997 09:49:45:200AM970527012Steve WolfeShot 12: MOve last point on ICEF4 from -.003 to 0.0
plasma - all the way down; well, to 1.63sec anyway.
A few bursts of vertical instability.
Density still looks ratty; it's taking gas all the way through.
Snipes thinks it's dithereing H-mode, I don't know about that.



May 27 1997 09:58:12:640AM970527013Steve WolfeShot 13: Enable Ar puff for this shot, no other changes.
plasma: two in a row. Shorter. ends at 1.46sec.

Breakdown is not as good, only 90kA by 30msec, bd at 7.8sec
density looks cleaner, still calling for gas until .9sec.
li=1.27, beta_n~.5



May 27 1997 10:06:48:690AM970527014Steve WolfeShot 14: no changes
fizzle, base pressure was high
55kA fizzle! almost went
6.6msec breakdown.
no sign of it on ECE?


May 27 1997 10:12:16:370AM970527015Steve WolfeShot 15: no changes
base=1.3e-6
fizzle, late breakdown(10.8msec), like #10
Bz is there early. slightly negative Br.
I think it's a gas effect, but try a tiny Br tweak.

May 27 1997 10:20:40:500AM970527016Steve WolfeShot 16: Br from .0065 to .007
base=9.5e-7
fizzle.
Almost identical timing. Bz in plenty early, maybe too much.
May 27 1997 10:29:14:010AM970527017Steve WolfeShot 17: add two msec to pre-puff, back to 20msec
dud. ??
Null looks worse, but not that bad.
May 27 1997 10:40:27:820AM970527018Steve WolfeShot 18: EF4 back to -1310 (from -1300)
fizzle. 80kA!
seems to be moving in, maybe bad vertical location.
May 27 1997 06:43:36:060PM970527019Steve WolfeShot 19: br back to .0065 from .007
fizzle. bd at 5msec (like last shot)
only (?!) 45kA this time. Why aren't these going???

May 27 1997 10:56:19:840AM970527020Steve WolfeShot 20: RCUR offset to 6900 from 6950.
fizzle. 45kA again. early breakdown 5msec
Br looks a little negative.

May 27 1997 11:10:36:030AM970527021Steve WolfeShot 21: reload shot 9: note that RCUR is back to 6950, pre-puff back to 18msec

plasma. Maybe it was the reload, maybe it was just time.
Early bd, long hesitation at 50kA.
It seems to start outside and move in, then swing back out.
disruption is at 1.47sec., voltage is rising through pulse.
li is steady around 1.25
May 27 1997 11:22:02:560AM970527022Steve WolfeShot 22: No changes.
base=1.6e-6

plasma again. 1.46sec.
early breakdown, smooth current rise.
May 27 1997 11:32:08:910AM970527023Steve WolfeShot 23: No changes.
base=1.8e-6
plasma. 1.46 sec.

breakdown at 6.7msec, very slight hesitation
li=1.25, surface voltage rises to 1.45V during shot.
May 27 1997 11:44:59:490AM970527024Steve WolfeShot 24: Move Argon pulse to .5sec (from .3)
base=1.5e-6
plasma. disrupts about the same time
bd at 5.8msec

JR wants about 6 or 7 more shots to cross-calibrate the Hirex

May 27 1997 11:51:11:790AM970527025Steve WolfeShot 25: No changes
base=2.3e-6
fizzle. not too surprising, I just hope we haven't lost it.
Looks like a huge teflon burst; 9e-6 at t=-.5sec

bd at 6.75msec, no current rise. CII was at .02 (not .002)!
May 27 1997 11:59:59:570AM970527026Steve WolfeShot 26: No changes
base=1.4e-6
dud.
no fluorocarbon that time.
Null looks terrible, no obvious supply problems.

May 27 1997 12:06:59:290PM970527027Steve WolfeShot 27: No changes, see if it recovers on it's own
base=1.0e-6

fizzle. looked weak.
bd at 10msec,CII at .004 and rises
bz in late, slight negative br



May 27 1997 12:14:33:640PM970527028Steve WolfeShot 28: no changes
base=8.7e-7
plasma, it came back on it's own.
bd at 5.5msec, some hesitation.
Still disrupting at 1.45 sec or so,
density is almost flat, still asking for gas, possibly from the pre-programing.




May 27 1997 12:21:39:610PM970527029Steve WolfeShot 29: no changes
base=2.0e-6
fizzle. 50kA. bd at 7.3msec
Bz not coming in fast enough.


May 27 1997 12:29:01:350PM970527030Steve WolfeShot 30: RCUR offset to 6850 from 6950. (that would seem to be the wrong way, but we'll see.)
base=1.3e-6
dud.
Null looks a little messy, but why didn't it at least fizzle.

May 27 1997 12:35:43:620PM970527031Steve WolfeShot 31: RCUR offset to 6850 from 6950. (that would seem to be the wrong way, but we'll see.)
try again.
two duds in a row. It can't be the RCUR tweak, that doesn't turn on until 6msec
May 27 1997 12:46:46:510PM970527032Steve WolfeShot 32: RCUR offset back to 6950 from 6850.
base=8.7e-7
plasma: 5.7msec breakdown, visible on all ece channels but #9
Disrupts at 1.45 again.
The EF4 voltage is doing a funny thrash, the hybrid is asking for it.
May 27 1997 12:54:41:370PM970527033Steve WolfeShot 33: Get rid of early point on EF4 current trace, it was asking for a rather slow ramp.
base=1.9e-6

plasma: When they go, they look the same.
Still getting the EF4 voltage thrash
May 27 1997 01:07:52:940PM970527034Steve WolfeShot 34: no changes
base=2.0e-6
alternator lost voltage. No shot.
try that one again, alternator crew monitoring voltage
base=1.4e-6

No TF, OH1, EF1's. Got OH2's, EF2's, EF3, EF4
Bizarro!
May 27 1997 01:19:55:850PM970527035Steve WolfeShot 35: no changes
Try again.
base=1.1e-6

short disruptive. 337 msec, 800kA.
something strange at 0.27sec, density starts to pump out.
May 27 1997 01:37:09:260PM970527036Steve WolfeShot 36: no changes
Try again after waiting for pressure to drop.
base=1.0e-6

plasma, full length (1.51sec)
bd at 6.4msec
some injections.
May 27 1997 01:42:35:400PM970527037Steve WolfeShot 37: no changes
base=2.1e-6
plasma 1.5sec
bd at 6.2msec, nice rise.

May 27 1997 01:54:08:010PM970527038Steve WolfeShot 38: no changes
base=2.5e-6

plasma: 1.48sec
5.6msec bd, good rise.

JR has finished his cross-calibration/alignment.
We will have a cell access for the RF people and others
May 27 1997 02:44:48:370PM970527039Steve WolfeShot 39: no changes from 38, except waiting 47 minutes.
NOte Alex tried opening his gate valve, which is blanked off and was closed last Friday.
Pressure went to the high 5 scale, then came down after his valve closed again with a fault.

base=7.9e-7
plasma. 1.5sec.
bd at 5.6msec, some hesitation in current rise, CII at .006
May 27 1997 02:49:01:510PM970527040Steve WolfeShot 40: No changes
base=2.2e-6

plasma: standard.
May 27 1997 03:03:31:000PM970527041Steve WolfeShot 41: Move seg2 rcur from .667 to .670 for Granetz
(should move edge by 6mm)
base=2.1e-6

plasma, to the usual end point
late breakdown (6.5msec)
right gap is 12mm
May 27 1997 03:11:23:890PM970527042Steve WolfeShot 42: repeat
base=2.0e-6

fizzle. Oh well.
very late bd (14msec) never had a chance.
slight negative br, no worse than many that went.
May 27 1997 03:18:24:200PM970527043Steve WolfeShot 43: repeat, see if it comes back
base=1.4e-6
dud. Where did it go?



May 27 1997 03:25:42:280PM970527044Steve WolfeShot 44: One more chance, then I tweak something
base=1.1e-6

plasma:
5.5msec bd, strong current rise,
lasts to 1.46sec, 11 to 12mm outer gap.



May 27 1997 03:37:05:020PM970527045Steve WolfeShot 45: no changes
base=1.8e-6

plasma 1.44 sec,
bd at 5.9msec, strong current rise
NINJA He puff at 0.7 sec, no sign of them on the density or zmeter
RF fired sometime, at some level



May 27 1997 03:50:34:140PM970527046Steve WolfeShot 46: no changes
base=1.7e-6
NINJA trying again with the right (?) capillary

plasma, same length.
We are seeing a shower of sparks on the lower left of the tv.
bd at 5.4msec
Note: Amanda has applied a new calibration to the ECE.
NINJa people think they see the lines on their spectrometer.
RF is firing, but no sign of them on ECE.


May 27 1997 03:59:24:800PM970527047Steve WolfeShot 47: no changes
base=1.8e-6

plasma, same length.
rf is seeing 100% reflection
He signal is saturating.
May 27 1997 04:09:58:100PM970527048Steve WolfeShot 48: no changes
base=2.5e-6

plasma, no sparks this time.
same length
RF now claims to be net 30kW, but Yuichi says not to believe the numbers


May 27 1997 04:19:02:630PM970527049Steve WolfeShot 49: Extend OH1 voltage pre-program at end of shot.
base=1.9e-6

plasma, no sparks this time.
same length
RF now claims to be net 30kW, but Yuichi says not to believe the numbers

plasma: a little longer,1.54sec

May 27 1997 04:25:05:230PM970527050Steve WolfeShot 50: Extend gains on RXL, ZXL, RXU, ZXU to 1.7+ sec
base=2.3e-6

plasma , sparks are back.
exactly the same length 1.55sec
May 27 1997 04:37:02:120PM970527051Steve WolfeShot 51: Extend OH1 voltage program to 1.75sec
base=2.6e-6

plasma, no sparks
looks the same length.
camac errors on magnetics data. LPE on Traq3; TWF rescued the data.

May 27 1997 04:46:45:840PM970527052Steve WolfeShot 52: Extend EF4 current program to 2 sec
base=2.0e-6

plasma, sparks again.
1.57sec,
UMd reports H/(H+D)=15%
RF reads nearly 80kW.

May 27 1997 04:59:29:870PM970527053Steve WolfeShot 53: Hold RCUR out longer
base=1.9e-6

plasma, still has sparks.
RF claims 200kW

May 27 1997 05:16:36:370PM970527054Steve WolfeShot 54: No changes
base=2.0e-6

plasma, no sparks
No longer, no shorter.
Leave the rampdown to Bob tomorrow

RF is claiming 300kW on this one. (or kTakase, perhaps)


Engineering Operator Comments
ShotTimeTypeStatusComment
107:48:56:760AMTestOkoh test
208:02:38:730AMPlasmaOkNo BD
308:17:51:940AMPlasmaOkno faults, no bd
408:27:59:250AMPlasmaOkno faults,nobd
508:36:12:480AMPlasmaOk
608:44:00:020AMPlasmaOk
708:51:48:490AMPlasmaOk
808:58:53:300AMPlasmaOk
909:06:22:570AMPlasmaOk
1009:18:35:670AMPlasmaOk
1109:31:34:900AMPlasmaOk
1209:42:39:070AMPlasmaOk
1309:52:25:840AMPlasmaOk
1410:01:17:470AMPlasmaOk
1510:08:12:130AMPlasmaOk
1610:15:14:300AMPlasmaOk
1710:24:04:040AMPlasmaOk
1810:31:48:670AMPlasmaOk
1910:42:21:440AMPlasmaOk
2010:50:38:290AMPlasmaOk
2111:02:44:590AMPlasmaOk
2211:14:56:540AMPlasmaOk
2311:25:36:970AMPlasmaOk
2411:38:17:970AMPlasmaOk
2511:45:31:220AMPlasmaOk
2611:53:15:600AMPlasmaOk
2712:01:32:650PMPlasmaOk
2812:08:34:960PMPlasmaOk
2912:17:05:350PMPlasmaOk
3012:23:54:620PMPlasmaOk
3112:32:05:350PMPlasmaOk
3212:41:12:900PMPlasmaOk
3312:49:59:390PMPlasmaOk
3412:58:11:940PMPlasmaBadmissing power supplies
3501:11:33:180PMPlasmaOk
3601:31:16:730PMPlasmaOk
3701:39:32:240PMPlasmaOk
3801:47:03:510PMPlasmaOk
3902:38:38:900PMPlasmaOk
4002:46:22:000PMPlasmaOk
4102:56:08:680PMPlasmaOk
4203:05:30:430PMPlasmaOk
4303:13:41:170PMPlasmaOk
4403:20:40:550PMPlasmaOk
4503:30:29:270PMPlasmaOk
4603:41:29:710PMPlasmaOk
4703:53:06:970PMPlasmaOk
4804:01:34:000PMPlasmaOk
4904:12:14:780PMPlasmaOk
5004:21:16:040PMPlasmaOk
5104:28:40:800PMPlasmaOk
5204:40:14:340PMPlasmaOk
5304:52:11:510PMPlasmaOk
5405:03:09:400PMPlasmaOkend of run 54 shots