Alcator C-Mod Run 950406 Information

Back to runs

Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Yuichi Takase (shots 1-36)

Operators
Session leader(s):Yuichi Takase
Physics operator(s):Steve Horne
Engineering operator(s):Vinny Bertolino,Joe Daigle

Engineering Operator Run Comment
G/ Horne

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:13:303PM
Author: To Be Determined
RF Conditioning / Reversed Field L-Mode Run

SL: Takase
PO: Horne
EO: Bertolino/Daigle

Objectives:
1. Check operation of RF protection systems
2. RF conditioning
3. Switch to reversed-field L-Mode run (if 1. and 2. accomplished)
4. Test RF power modulation

Objectives 1., 2., and 4. were accomplished.
There is still some work that needs to be done with respect to
objective 1., but both systems are now operational.

Start from 950405022, nel_04=1.e20

01 Fiz
02 Fiz
03 Fiz
04 Fiz
05 Fiz
06 Pla Balance trips on both
07 Fiz
08 Pla Transmitter #2 tripped before shot
09 Fiz
10 Fiz
11 Fiz
Abandon TF ramp breakdown, go to 5.3T (flat TF) breakdown
12 Dud
13 Fiz
14 Pla Good shot! P_D=1.1MW (Testing protection circuits)
15 Pla
16 Pla Both antennas on
17 Pla
18 Pla
19 Pla
20 Pla D-port power modulation
21 Pla nel_04=1.4e20 (was 1.0e20)
22 Pla
23 Pla
24 Pla raise zmagx to -0.5cm (was -1.5cm)
25 Pla
26 Pla
27 Pla Rgap=1.8cm (was 2.1cm)
28 Pla Rgap=1.5cm
29 Pla zmagx=+0.5cm, density pump-out
30 Pla
31 Pla zmagx=+0.0cm
32 Pla
33 Pla upper X-pt moved out, no density pump-out, 1MW from each antenna
34 Pla density punp-out is back
35 Pla upper X-pt moved out, no density pump-out, 1MW(D) + 1.5MW(E)
36 Pla 1MA, no E-port

Physics Operator Summaries
Entered: Jul 7 2004 04:36:53:770PM
Author: To Be Determined
run 950406

PO Horne
SL Takase
EO Bertolino,Daigle


This was an RF tuning run which bumped the original plan for today, which
required more RF power than was available this morning.
We began with yesterday's shot 950405020 which was a "startup on tf ramp".
After fiddling around till after 11:00 without a reliable startup,
we decided to develop a normal startup. Engineering setup was as on shot
950331038. We had a dud and a fizzle, then began to roll.
Mflux looked marginal but was fairly reproducible. Given the disgusting
early morning behavior I decided not to touch the startup until
we got a fizzle; the result was 23 plasmas in a row
with decent rampdowns and no serious disruptions.

Starting with shot 27 made minor tweaks to develop a starting plasma for
the run which was bumped today. This was successful; shot 36 ran at 1 MA and
shape, density should be close to what Martin wants.

I reduced EF2_BY_EF4 and IC_EF4 gains significantly because it looked like it may have
been inducing an oscillation. Note that it takes a LONG time for ef4 fields to soak
through the steel.

Wolfe argued based on MFLUX for raising the OH1 precharge current by of order 50-100 A.
If startup tomorrow is fizzly keep this in mind.

Keep an eye on the a side plenum pressure. I believe that when it drops to 17 lbs
it should be raised back to 19-20.

RF group seems happy. See Yuichi's report.

================= Shot log ============

1 fizzle
2 no change -- fizzle
3 > drop ef4 15 A
> drop br offset by 5.e-4 T to 0.
4 > 50 A less in oh1. = about half a mt in bz
5 > ic_ef4 down 30 A (2 mt)
> fill to 2.2e-5
6. > The flux plots seem to imply that the OH current tweak was the wrong direction,
though the
scatterplot shows oh1 current now tracks yesterday's shots. Try oh1 up 100 A.
PLASMA!!

7 Nasty vertical oscillation on slow timescale. Also note
ef2 error is pushing ef4 way too hard.
drop ef2/eff p from 4 to 1.
Reduce density ramp.
FIZZLE...
Early breakdown though.

8. fill to 1.8e-5
Take br offset back up to .0005.

That worked. There is an oscillation at 60 hz on the ef1 u between .4 and .6,
also at different time on ef1l. Vinnie says this is related to the
last changes in power supplies -- the "new boards".

9 Dud. scatterplot and flux plot agree bz too negative.Take ef4 up 30 A.
Raise fill to 2.0. e -5.
Fizzle. Flux plots look fairly good --

10 fill to 2.2e-5.

11 fizzle.

========= Bail out of this.=====

SINCE NO MORE RUNS DEPEND ON THIS STARTUP SCENARIO, ABANDON IT AND GO BACK TO FULL
FIELD STARTUP.
Basically aim at 950331038. Compensate tf half-turn with ef4 = -1085 A.
Don't know what to expect for OH1 so take a shot with present setting.

Dud -- take ef4 up to 1200 A.

13. Fizzle. take br .5 mt more negative, fill to 2.0e-5.

14 PLASMa. Ramped down nicely.
Squinting at flux plot seems to imply
we should raise oh1 current by perhaps 50 A or so.
But no changes for next.
Plan is to make no pre-emtive changes to startup --
15 Plasma.
16 Plasma
17 Plasma. ECE signal is creeping to uoter channels.
18 Plasma
19 Plasma. Try to fix the disruption on rampdown by an rcur tweak.
20 Plasma, the rampdown tweak worked. RF wants 1.4e20 nl. Do that.
Also tweak ef4 current between .1 and .2 sec.
21 Plasma. Tweak density to come up earlier, and drop ic_ef4 current late from 2
to 1.5
22 plasma
23 plasma

24 plasma. RF want's zcur more centered. Martin wants more elongation.
Raise zcur from -2. cm to -1. cm.

25 That worked. Density rise not optimal --
plenum pressure to 19 from 17.1; slow ip ramp slightly.

26 Plasma. For next shot, begin to prepare for Martin's run.
Move rcur out 2 mm to reduce outer gap slightly.

27 plasma. outer gap still too large. Move rcur another 2 mm.
Also notice that bounce scope implies we're near runaway territory.
O'Shea confirms non-thermal behavior.
Raise fill from 2.0 e-5 to 2.1e-5

28 plasma. ECE looks better.
Enable argon for next shot.
Raise zcur 1 cm to to zero;

29 Plasma. That was .5 cm high. Repeat; prepare to drop it next shot.
zcur predictor says it's centered.

30 Plasma. Drop zcur to -.5 cm for next. ECE looks ok.
31 plasma. z position looks good. Something takes a bite
out of the density at .74 sec. Not obvious what.
There's a slow oscillation between ic_ef4 and ic_ef2. Drop ef2by ef4
gain from 1.0 to 0.5.


32 Plasma. Density glitch still there.
Try to move the upper xpoint out a bit by increasing zxu gain .
Also drop ic_ef4 p from 1.5 to 1.0

33 Plasma. Density glitch gone. efit movie confirms upper x-point behavior has
changed.

34 Plasma. Density glitch came back; push gain on zxu up to 9.9
That worked.

35. Worked. Plenum pressure is down to 17. Ask for 19. Got 20.
Next and last shot, try 1 MA.
36 GOT IT.


================ end log =============

Session Leader Comments
Apr 6 1995 09:30:20:340AM950406001Yuichi TakaseRF Conditioning / Reversed Field L-Mode Run

Objectives:
1. Check operation of RF protection systems
2. RF conditioning
3. Switch to reversed-field L-Mode run (if 1. and 2. accomplished)
4. Test RF power modulation

Start from 950405022, nel_04=1.e20

Shot 01:
Fizzle

Apr 6 1995 09:30:41:770AM950406002Yuichi TakaseShot 02:
Fizzle

Apr 6 1995 09:30:51:140AM950406003Yuichi TakaseShot 03:
Fizzle

Apr 6 1995 09:30:59:780AM950406004Yuichi TakaseShot 04:
Fizzle

Apr 6 1995 09:31:08:460AM950406005Yuichi TakaseShot 05:
Fizzle

Apr 6 1995 02:07:19:990PM950406006Yuichi TakaseShot 06:
Plasma
RF trips on imbalance

Apr 6 1995 02:08:03:430PM950406007Yuichi TakaseShot 07:
Fizzle

Apr 6 1995 02:10:55:990PM950406008Yuichi TakaseShot 08:
Plasma
Transmitter #2 tripped before shot.

Apr 6 1995 02:11:12:770PM950406009Yuichi TakaseShot 09:
Fizzle

Apr 6 1995 02:11:20:790PM950406010Yuichi TakaseShot 10:
Fizzle

Apr 6 1995 02:11:29:600PM950406011Yuichi TakaseShot 11:
Fizzle

Apr 6 1995 02:13:11:130PM950406012Yuichi TakaseShot 12:
Abandon TF ramp breakdown, go to 5.3T (flat TF) breakdown.
Dud

Apr 6 1995 02:13:30:790PM950406013Yuichi TakaseShot 13:
Fizzle

Apr 6 1995 02:14:08:970PM950406014Yuichi TakaseShot 14:
Plasma
Good shot!
Testing protection circuits

Apr 6 1995 02:14:55:340PM950406015Yuichi TakaseShot 15:
Plasma

Apr 6 1995 02:16:44:110PM950406016Yuichi TakaseShot 16:
Plasma
Both antennas on.

Apr 6 1995 02:16:59:810PM950406017Yuichi TakaseShot 17:
Plasma

Apr 6 1995 02:21:27:240PM950406018Yuichi TakaseShot 18:
Plasma
INCAA_3 error

Apr 6 1995 02:26:13:810PM950406019Yuichi TakaseShot 19:
Plasma
P_E=0.5MW

Apr 6 1995 02:26:47:990PM950406020Yuichi TakaseShot 20:
Plasma
D-port power modulation

Apr 6 1995 02:28:36:720PM950406021Yuichi TakaseShot 21:
Plasma
nel_04=1.4e20 (was 1.0e20)
D-port tripping

Apr 6 1995 02:36:07:420PM950406022Yuichi TakaseShot 22:
Plasma

Apr 6 1995 02:36:18:860PM950406023Yuichi TakaseShot 23:
Plasma

Apr 6 1995 02:37:03:480PM950406024Yuichi TakaseShot 24:
Plasma
zmagx = -0.5cm (was -1.5cm)

Apr 6 1995 02:37:21:670PM950406025Yuichi TakaseShot 25:
Plasma

Apr 6 1995 03:30:42:870PM950406026Yuichi TakaseShot 26:
Plasma

Apr 6 1995 03:31:09:000PM950406027Yuichi TakaseShot 27:
Plasma
Rgap=1.8cm (was 2.1cm)

Apr 6 1995 03:31:35:160PM950406028Yuichi TakaseShot 28:
Plasma
Rgap=1.5cm

Apr 6 1995 03:31:52:740PM950406029Yuichi TakaseShot 29:
Plasma
zmagx=+0.5cm

Apr 6 1995 03:32:16:300PM950406030Yuichi TakaseShot 30:
Plasma

Apr 6 1995 04:19:54:000PM950406031Yuichi TakaseShot 31:
Plasma
zmagx=+0.0cm
Edge density rearrangement trips D-port (since shot 29).

Apr 6 1995 04:20:40:060PM950406032Yuichi TakaseShot 32:
Plasma
Edge density rearrangement trips D-port (since shot 29).
Push upper X-pt away for next shot.

Apr 6 1995 04:21:26:440PM950406033Yuichi TakaseShot 33:
Plasma
Push upper X-pt away.
Good density, good RF (1MW from each).

Apr 6 1995 05:30:26:840PM950406034Yuichi TakaseShot 34:
Plasma
density punp-out is back

Apr 6 1995 05:30:55:760PM950406035Yuichi TakaseShot 35:
Plasma
upper X-pt moved out again, no density pump-out, 1MW(D) + 1.5MW(E)

Apr 6 1995 05:31:15:090PM950406036Yuichi TakaseShot 36:
Plasma
1MA, no E-port

Physics Operator Comments

Engineering Operator Comments
ShotTimeTypeStatusComment
108:33:35:910AMPlasmaOkno faults
208:46:11:200AMPlasmaOkno faults
309:00:57:310AMPlasmaOkno faults
409:11:50:610AMPlasmaOkno faults
509:22:46:260AMPlasmaOkno faults
609:35:46:400AMPlasmaOkno faults
709:59:06:720AMPlasmaOkno faults
810:11:52:140AMPlasmaOkno faults
910:27:12:700AMPlasmaOkno faults
1010:36:02:460AMPlasmaOkno faults
1110:45:22:280AMPlasmaOkno faults
1211:11:37:050AMPlasmaOkno faults
1311:21:39:070AMPlasmaOkno faults
1411:33:58:610AMPlasmaOkno faults
1511:50:24:530AMPlasmaOkno faults
1612:07:25:940PMPlasmaOkno faults
1712:22:29:730PMPlasmaOkno faults
1812:33:56:120PMPlasmaOkno faults
1912:46:22:660PMPlasmaOkno faults
2012:58:59:290PMPlasmaOkno faults
2101:14:17:330PMPlasmaOkno faults
2201:28:10:060PMPlasmaOkNo Faults.
2301:41:04:140PMPlasmaOkNo Faults.
2401:53:06:440PMPlasmaOkNo faults.
2502:14:57:750PMPlasmaOkNo Faults.
2602:25:59:030PMPlasmaOkNo Faults.
2702:39:17:620PMPlasmaOkNo faults.
2802:53:33:170PMPlasmaOkNo Faults.
2903:07:38:440PMPlasmaOkNo faults.
3003:19:12:610PMPlasmaOkNo Faults.
3103:32:30:920PMPlasmaOkNo Faults.
3203:49:28:110PMPlasmaOkNo Faults.
3304:05:45:360PMPlasmaOkno faults.
3404:22:31:850PMPlasmaOkNo Faults.
3504:40:09:790PMPlasmaOkNo faults.
3604:53:31:760PMPlasmaOkNo Faults.