Alcator C-Mod Run 941118 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:John Goetz (shots 1-43)

Operators
Session leader(s):John Goetz
Physics operator(s):Ian Hutchinson
Engineering operator(s):Vinny Bertolino

Engineering Operator Run Comment
first plasmas

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:11:290PM
Author: To Be Determined
Session Leader/ Physop Summary 18 Nov 94

Ian Hutchinson, John Goetz, Vinnie Bertolino

Objectives:
(1) 5 MC of plasma.
(2) Reliable startup.
(3) Successful Fiducial Shot.
(4) A more useful fiducial, with some gas puff variation.

Ideas to try: Result:
Fiddle with the B_z ramp rate. Done a lot, without obvious help.
Tweak B_r Seemed to scan through the best place.
Lower the gas puff after about 0.1 s. Did not attempt.

Scorecard:
Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax
1 0.000 0.019 2 0.000 0.021
3 0.000 0.021 4 0.000 0.021
5 0.000 0.026 6 0.273 0.187
7 0.000 0.021 8 0.000 0.021
9 0.000 0.021 10 0.000 0.021
11 0.714 0.515 12 0.000 0.016
13 0.000 0.019 14 0.000 0.021
15 0.000 0.083 16 0.000 0.024
17 0.000 0.021 18 0.000 0.026
19 0.000 0.019 20 0.000 0.021
21 0.162 0.179 22 0.000 0.021
23 0.000 0.021 24 0.000 0.024
25 0.000 0.019 26 0.000 0.021
27 0.000 0.021 28 0.000 0.026
29 0.000 0.024 30 0.572 0.522
31 0.000 0.019 32 0.000 0.021
33 0.000 0.021 34 0.000 0.021
35 0.000 0.021 36 0.000 0.021
37 0.000 0.021 38 0.000 0.021
39 0.000 0.021 40 0.000 0.024
41 0.000 0.024 42 0.000 0.024
43 0.343 0.512
Finished summary for 941118 Total of 43 shots.
43 shots. 6 plasmas. 37 fizzles. 0 duds.
Fizzle = gt 15 lt 50kA.

There was no ECDC this morning because of PEI problems.
Starting from Shot 32 of yesterday. No changes for the first shot.
Reloaded to make sure any fixes are not breaking it.

None of the objectives were achieved because the current ramp was so
poor. Plasmas that went were plagued by runaways. A strong
correlation was observed between the RGA 18 peak pump down and the
success of the shot. This seems to confirm the feeling that the poor
vacuum conditions are the major problem.

Detailed log:
Shot/Result
1.e-5 fill A-side.
1 Fiz Bdwn 5ms just like 32. Field gradient a little large. Chopper broken.
OH2 to -22200 from -22700 totake out half of the previous change.
2 Fiz Bdwn 4.5ms. 15kA current. Fields look good.
Lower fill to 8.e-6. No other changes.
3 Fiz Bdwn 4.5ms very similar to 2.
Lowered EF3 voltage by adding a point (8ms,2400) to try reducing the Bz
ramp rate.
4 Fiz Longer Ip duration. Slight radial field showing. F16 broke. zmeter .04.
Raised B_r offset to 5 from 4.5 mT. Removed TV Filter
5 Fiz Looked better on mfil and Ip. Bdwn slightly later 4.7ms.
B_r offset to 5.5mT.
6 Pla 180kA, 350ms. Bdwn 5.5ms. A truly ugly plasma. looks like the B_r offset
is bad for breakdown but good for current ramp. zmeter .06.
Straight repeat,
Halpha filter back.
7 Fiz Just didn't go.
Lowered EF3 to 2300 at 8ms point.
8 Fiz Bdwn 5.7ms. Still close.
Lowered EF3 to 2100.
9 Fiz some spikes on Z-meter and Halpha.
Lowered EF3 to 1900.
10 Fiz Spikes earlier on z/Ha.
Put EF3 to 2500. This is close to the original evolution.
11 Pla Runaways. 500kA, 0.7 s. Z-meter drops ot .05
Repeat
12 Fiz Z-meter rises off scale! 10 kA
RCUR early demand to 0.68m from 0.7m.
13 Fiz 12 kA zmeter still bad.
Lowered OH1 voltage at 24ms point to 130V from 150V. Idea to give a more
rapid filed ramp, while we are waiting for the machine to pump.
14 Fiz 15kA, zmeter over to .06. Very little change in Bz evolution.
Oh1 to 100V.
15 Pla Runaways. 80kA @60 ms.
OH1 to 50V also to 50V @ 5ms from 90V.
16 Fiz 15 kA. zmeter over to .05.
Oh1 to 0V 5-24ms.
17 Fiz 15kA, no zmeter spike.
Repeat.
18 Fiz 20 kA. zmeter .06, Big Halpha spike. The OH1 changes now have Bz and .043T
@ .03s vs shot 13 .037T. Ramp rate has thus changed by 15% using about 100V
difference on OH1.
Oh1 to -50V
19 Fiz 15kA.Seem to have gone too far in OH1. No Ha spike.
Oh1 to +25V @ 5ms. (24 -50V).
20 Fiz 15kA zmeter .06. Small Ha spike.
OH1 to 100V@5ms
21 Pla 150 kA .25s. zmeter .05 but with second rise. No Ha spike.
OH1 to -100V @ 24ms.
22 Fiz 15kA. Small Ha spike.
Repeat
23 Fiz Highly similar.
Increase OH1 to +200V at 5ms.
24 Fiz 18kA nearly.
Oh1 to 250 @ 5ms.
25 fiz
Pulse gas moved 15 ms later
26 fiz
Raise fill to 1.0e-5
27 fiz
Raise to 1.2e-5
28 fiz
Reload of 11.
29 Fiz
Repeat
30 Pla Runaway 500kA.
Repeat
31 fiz Big zmeter excursion. 12kA.
Reload shot 13 to get back the RCUR programming.
ADDED OH1 points (8ms,100V),(10ms,0V)
Changing the definition of current to the reading. without vacumm subtracted.
32 fiz 22kA
OH1 to (10,-100V).
33 Fiz 22kA, zmeter .05, secon Ha blip.
EF4 to -1125 from -1110.
34 Fiz 22kA Slight UV tomo signal. Maybe hards.
OH1 to (10,+200V)
35 Fiz 22kA, no zmeter burnout.
EF4 to -1140.
36 Fiz 22kA. 5ms bdown.
lowered B_r offset to 5.e-3.
37 Fiz 22kA not much different.
Oh1 (10,+300V)
38 Fiz 22kA no obvious diffs.
EF4 to -1155
39 Fiz 22kA slightly longer duration, bdown @ 6ms.
Fill to 1e-5
40 Fiz 24kA
Fill to 1.2e-5
41 Fiz 23kA
Fill to 8e-6
42 Fiz 24kA
Reload shot 30
43 Pla Runaway shot as before. 18 Peak was down to -8.3 on the RGA. Horne claims
that this is the criterion.

Physics Operator Summaries

Session Leader Comments
Nov 18 1994 08:30:06:060AMJohn GoetzMini-proposal #041 -- Startup C-Mod in 1994

Start from 941117032 - a shot with an early breakdown and some 'good
tweaking' - no changes to make sure PCS cosmetic
changes haven't harmed anything.

Base pressure = 1.2e-7
No ECDC before this run due to PEI problems

Nov 18 1994 09:06:36:970AM941118001John Goetz941118001:
Fill pressure = 1.0e-5

Fizzle - breakdown at .005 sec, but no current rise.

No Chopper this shot - some switches were off


For 002: Change IC_OH2U to -22200A from -22700A to change the
gradients at breakdown time.

Nov 18 1994 09:21:40:890AM941118002John Goetz941118002:
Fill pressure = 1.0e-5

Fizzle - breakdown at .004 sec, more current than 001 - almost went
flux reconstructions show that the fields are very good ( even
at the .001Wb level )

[ Horne set maximum chopper on pulse to 2 sec ]


For 003:
lower fill pressure to 8.0e-6

Nov 18 1994 09:33:17:930AM941118003John Goetz941118003:
Fill pressure = 8.0e-6

Fizzle - breakdown at .004 sec, fields look good

For 004:
Add a point to V_EF3 - 2400V @ .008s - to try and slow down
the Bz ramp rate

Nov 18 1994 09:46:26:630AM941118004John Goetz941118004:
Fill pressure = 8.0e-6

Fizzle - breakdown at .004 sec, some Br on this shot
the current stayed up longer this shot but still didn't
take off

For 005:
Change offset on BR_0 to .005 from .0045 to try and keep the
radial field a little more positive.

Nov 18 1994 09:56:30:720AM941118005John Goetz941118005:
Fill pressure = 8.0e-6

Fizzle - breakdown at .005 sec
Halpha hangs around until .05 sec
plasma almost goes

For 006:
Continue the BR_0 offset experiment - change to .0055 from .005

Nov 18 1994 10:08:04:150AM941118006John Goetz941118006:
Fill pressure = 8.0e-6

Breakdown @ .0055 sec - slightly positive radial field at this time,
but the current ramp seems to like it

Plasma - .18MA @ .1 sec then decays until 0.36sec - disrupting all
the way home

For 007:
no changes - just try again

Nov 18 1994 10:18:05:010AM941118007John Goetz941118007:
Fill pressure = 8.0e-6

Breakdown @ .005 sec - Halpha light until .05sec

For 008:
lower the EF3 voltage to 2300V to slow down the Bz ramp

Nov 18 1994 10:34:26:270AM941118008John Goetz941118008:
Fill pressure = 8.0e-6

Fizzle - Breakdown @ .0055 sec - Halpha light until .05sec - almost
a burnout on the z-meter signal

For 009:
continue the Bz ramp rate experiment - lower the EF3 voltage to 2100V
to slow down the Bz ramp even further

Nov 18 1994 10:45:12:050AM941118009John Goetz941118009:
Fill pressure = 8.0e-6

Fizzle - Breakdown @ .0055 sec - Halpha light until .05sec
difficult to diagnose the EF3 experiment as shots 007, 008,
and 009 are very similar.

For 010:
continue the Bz ramp rate experiment - lower the EF3 voltage to 1900V
to slow down the Bz ramp even further

Nov 18 1994 10:59:51:490AM941118010John Goetz941118010:
Fill pressure = 8.0e-6

Fizzle - Breakdown @ .006 sec - Halpha light until .05sec
good z-meter burn-out spike, but fills in very quickly

For 011:
continue the Bz ramp rate experiment, but go the other way - raise
the EF3 voltage to 2500V to increase the Bz ramp rate

Nov 18 1994 11:13:41:030AM941118011John Goetz941118011:
Fill pressure = 8.0e-6

Plasma - 0.5MA - disruption at 0.71 sec
Hard x-rays throughout
nl_05 less than 3e19 (max)
good cleaning shot - lots of Ar and other stuff released from the
walls (according to the RGA)

For 012:
no changes

Nov 18 1994 11:23:46:780AM941118012John Goetz941118012:
Fill pressure = 8.0e-6

Fizzle - breakdown at .006 sec - Halpha lasts until .04 -
less current - z-meter signal 8x shot 011.

For 013:
RCUR to 0.68 from 0.70 early in the shot (since shot 011
was riding out early)

Nov 18 1994 11:36:35:540AM941118013John Goetz941118013:
Fill pressure = 8.0e-6

Fizzle - breakdown at .006 sec - Halpha lasts until .04 -
z-meter signal 6x shot 011.

For 014:
V_OH1 to 130V @ .024 sec (was 150V) to continue the
Bz ramp experiments

Nov 18 1994 11:45:59:500AM941118014John Goetz941118014:
Fill pressure = 8.0e-6

Fizzle - breakdown at .005 sec - Halpha lasts until .04 -
z-meter signal 2x shot 011 - almost went

For 015:
V_OH1 to 100V @ .024 sec to continue Bz ramp experiment

Nov 18 1994 11:57:23:660AM941118015John Goetz941118015:
Fill pressure = 8.0e-6

Plasma/Fizzle - breakdown at .006 sec - .08MA until .06sec
lots of hard x-rays

For 016:
V_OH1 to 50V @ .024 sec to continue Bz ramp experiment
V_OH1 to 50V @ .005 sec (was 90V)

Nov 18 1994 12:10:54:950PM941118016John Goetz941118016:
Fill pressure = 8.0e-6

Fizzle - breakdown at .006 sec - hit something at .015 sec


For 017:
V_OH1 to 0V @ .024 sec to continue Bz ramp experiment
V_OH1 to 0V @ .005 sec

Nov 18 1994 12:19:34:030PM941118017John Goetz941118017:
Fill pressure = 8.0e-6

Fizzle - breakdown at .0055 sec - z-meter signal never comes down


For 018:
no changes

Nov 18 1994 12:28:42:030PM941118018John Goetz941118018:
Fill pressure = 8.0e-6

Fizzle - breakdown at .006 sec - hits something @ .015 sec -
good burn-out spikes on z-meter signal

For 019:
V_OH1 to -50V @ .005 & .024 sec (finish the Bz ramp
experiment by going well past the point of no return)

Nov 18 1994 12:38:44:220PM941118019John Goetz941118019:
Fill pressure = 8.0e-6

Fizzle - breakdown at .005 sec - hits something @ .012 sec -
gone too far with the change in Bz ramp rate

For 020:
V_OH1 to 25V @ .005 (choose a compromise voltage) & leave
the point at .024 the same

Nov 18 1994 12:48:58:380PM941118020John Goetz941118020:
Fill pressure = 8.0e-6

Fizzle - breakdown at .005 sec - hits something @ .013 sec

For 021:
V_OH1 to 100V @ .005 (back to where it was) & leave
the point at .024 the same

Nov 18 1994 01:03:37:420PM941118021John Goetz941118021:
Fill pressure = 8.0e-6

Plasma - max current .17MA, then decays until disruption @ .25 sec
Very disruptive through the whole shot
Still a pause in the current rise between .01 and .015 sec

For 022:
V_OH1 to -100V @ .024 sec to try and fix the current
hesitation

Nov 18 1994 01:13:29:320PM941118022John Goetz941118022:
Fill pressure = 8.0e-6
Fizzle - breakdown @ .005 sec - hits something @ .013 and then
slowly dies

For 023:
no changes - can't analyze the current rise with out a current rise

Nov 18 1994 01:22:48:170PM941118023John Goetz941118023:
Fill pressure = 8.0e-6
Fizzle - looks very similar to shot 022

For 024:
V_OH1 = 200V @ .005 sec (look for a drastic change in ramp)

Nov 18 1994 01:37:07:500PM941118024John Goetz941118024:
Fill pressure = 8.0e-6
Fizzle - almost went - a few more bits of current

For 025:
V_OH1 = 250V @ .005 sec (change the early Bz ramp rate)

Nov 18 1994 01:44:20:230PM941118025John Goetz941118025:
Fill pressure = 8.0e-6
Fizzle - looks very similar to shot 024

For 026:
slide PULSE_GAS_3 waveform +.020 sec

Nov 18 1994 01:53:23:550PM941118026John Goetz941118026:
Fill pressure = 8.0e-6
Fizzle - looks very similar to shot 024

For 027:
up the fill pressure to 1.0e-5

Nov 18 1994 02:09:08:310PM941118027John Goetz941118027:
Fill pressure = 1.0e-5
Fizzle - looks very similar to shot 024

For 028:
up the fill pressure to 1.2e-5

Nov 18 1994 02:12:48:820PM941118028John Goetz941118028:
Fill pressure = 1.2e-5
Fizzle - a few bounces - nothing spectacular

For 029:
Reload 941118011

Nov 18 1994 02:32:17:130PM941118029John Goetz941118029:
Fill pressure = 1.2e-5
Fizzle - hit something twice - good burn-out spike

For 030:
no changes

Nov 18 1994 02:46:17:620PM941118030John Goetz941118030:
Fill pressure = 8.0e-6
Plasma - makes it to .45MA - disruption @ .57 sec
Hard x-ray and density dump @ .225 sec, building to second dump at
disruption

For 031:
no changes

Nov 18 1994 02:53:30:940PM941118031John Goetz941118031:
Fill pressure = 8.0e-6
Fizzle - breakdown @ .006 - z-meter signal 6x shot 030

For 032:
Reload shot 941118013
Add two points to V_OH1 - 100V @ .008 sec and 0V @ .010 sec

Nov 18 1994 03:04:17:130PM941118032John Goetz941118032:
Fill pressure = 8.0e-6
Fizzle - breakdown @ .006 - initial burn-out on z-meter signal

For 033:
V_OH1 -> 100V @ .008 sec and -100V @ .010 sec

Nov 18 1994 03:18:29:360PM941118033John Goetz941118033:
Fill pressure = 8.0e-6
Fizzle - breakdown @ .006 - almost could have gone - good
burnout on the z-meter signal

For 034:
IC_EF4 -> -1125A from -1110A to check out response

Nov 18 1994 03:30:37:000PM941118034John Goetz941118034:
Fill pressure = 8.0e-6
Fizzle - breakdown @ .005 - hit something at .016 sec - tried to go

For 035:
V_OH1 to +200V @ .010 sec (was -100V)

Nov 18 1994 03:40:06:430PM941118035John Goetz941118035:
Fill pressure = 8.0e-6
Fizzle - breakdown @ .005 - hit something at .014 sec

For 036:
IC_EF4 to -1140A from -1125A

Nov 18 1994 03:51:02:140PM941118036John Goetz941118036:
Fill pressure = 8.0e-6
Fizzle - breakdown @ .005 - hit something at .012 sec

For 037:
offset on BR_0 = .005

Nov 18 1994 04:06:56:810PM941118037John Goetz941118037:
Fill pressure = 8.0e-6
Fizzle - breakdown @ .004 - a different sort of fizzle - less
radiated power, less Halpha

For 038:
V_OH1 = +300V @ .010 sec (was +200V)

Nov 18 1994 04:18:15:870PM941118038John Goetz941118038:
Fill pressure = 8.0e-6
Fizzle - breakdown @ .004 - an attempt to burn-out

For 039:
IC_EF4 to -1155A from -1140A

Nov 18 1994 04:28:48:310PM941118039John Goetz941118039:
Fill pressure = 8.0e-6
Fizzle - breakdown @ .006 - Halpha light lasts longer

For 040:
Fill pressure = 1.0e-5

Nov 18 1994 04:37:08:950PM941118040John Goetz941118040:
Fill pressure = 1.0e-5
Fizzle - breakdown @ .006 - a lot like shot 039

For 041:
fill pressure to 1.2e-5

Nov 18 1994 04:43:36:290PM941118041John Goetz941118041:
Fill pressure = 1.2e-5
Fizzle - breakdown @ .006 - a lot like shot 039

For 042:
fill pressure to 8.0e-6

Nov 18 1994 04:51:07:040PM941118042John Goetz941118042:
Fill pressure = 8.0e-6
Fizzle - breakdown @ .007 - an attempt at burn-out - more radiated
power

For shot 043:
Reload shot 941118030

Nov 18 1994 05:02:42:610PM941118043John Goetz941118043:
Fill pressure = 8.0e-6
Plasma - lots of hards throughout - 0.5MA
Hards dump at .325 sec - disruption @ .340 sec
Nl_05 ~ 1.5e19

Physics Operator Comments

Engineering Operator Comments
ShotTimeTypeStatusComment
108:52:21:750AMPlasmaOkno chopper,flash
209:14:03:620AMPlasmaOkno faults
309:23:56:250AMPlasmaOkno faults
409:35:08:210AMPlasmaOkno faults
509:47:52:520AMPlasmaOkno faults
609:58:33:230AMPlasmaOkno faults
710:10:20:720AMPlasmaOkno faults
810:24:34:690AMPlasmaOkno faults
910:34:40:030AMPlasmaOkno faults
1010:47:08:270AMPlasmaOkno faults
1110:58:16:990AMPlasmaOkno faults
1211:13:51:800AMPlasmaOkno faults
1311:25:47:820AMPlasmaOkno faults
1411:37:34:410AMPlasmaOkno faults
1511:47:56:550AMPlasmaOkno faults
1612:00:53:690PMPlasmaOkno faults
1712:11:49:390PMPlasmaOkno faults
1812:20:08:050PMPlasmaOkno faults
1912:30:32:180PMPlasmaOkno faults
2012:42:15:340PMPlasmaOkno faults
2112:54:04:890PMPlasmaOkno faults
2201:06:15:820PMPlasmaOkno faults
2301:15:40:030PMPlasmaOkno faults
2401:28:03:450PMPlasmaOkgood shot
2501:38:23:250PMPlasmaOkno faults
2601:47:05:080PMPlasmaOkgood shot but EF3 went into forced shutdown after shot
2701:58:35:790PMPlasmaOkno faults
2802:07:32:470PMPlasmaOkno faults
2902:18:37:240PMPlasmaOkno faults
3002:33:32:570PMPlasmaOkno faults, good plasma 520KA
3102:46:06:900PMPlasmaOkno faults
3202:55:31:570PMPlasmaOkno faults
3303:10:59:240PMPlasmaOkno faults
3403:23:02:230PMPlasmaOkno faults
3503:32:09:860PMPlasmaOkGood shot
3603:45:44:940PMPlasmaOkno faults
3703:58:32:200PMPlasmaOkno faults
3804:09:52:160PMPlasmaOkno faults
3904:20:19:510PMPlasmaOkno faults
4004:30:19:360PMPlasmaOkno faults
4104:39:15:610PMPlasmaOkno faults
4204:47:10:910PMPlasmaOkno faults
4304:56:45:660PMPlasmaOkno faults