Alcator C-Mod Run 930729 Information

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Miniproposal:
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Session Leader:Francesca Bombarda (shots 1-35)

Operators
Session leader(s):Francesca Bombarda
Physics operator(s): Unknown
Engineering operator(s): Unknown

Engineering Operator Run Comment
First Transport Scan attempt

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:08:100PM
Author: To Be Determined

From: LEADER::BOMBARDA
Date: 29-JUL-1993 18:34:30
Description: summary of run 930729

The purpose of the run was to measure Ti and Te profiles, as specified in the
MP008, with the HIREX spectrometers. Of course, argon was injected.

We started by picking one good discharge from the day before, 930728025
, which had a long current flat top at about 420 kA and a relatively flat
density as well. It took 6 fizzles before we could obtain a plasma, with small
adjustments on the OH1 and OH2 voltages, EF2 gains, and fill pressure up and
down (the first plasma had 1.e-5).
Shots #7 through #9 were all good, but we played around with the fill pressure
and the A port gas valve puffs to get a flat density as early as possible.
That also helped to get rid of the peak seen in the soft x-ray signal at 0.2 sec.
We also tried to to anticipate the argon puff, but the next four shots were
duds, in spite of our lowering the fill pressure and not putting argon at all.
In fact, we did get plasma again when turned the fill pressure up to 1.2e-5,
then lowered it again to 1.0e-5 for the next shot, which was very good, and
virtually equal to #10. Shots #16, 18 and 19 were all very similar
(#17 was a fizzle), and we used them for scanning the spectrometers across the
plasma section.
Next, we tried to go up in density, and although we did get other 5 shots
with plasma, from #21 to #26, they were not very nice and the density didn't get
any higher. #29 was another dud, and after that we decided to scan the low
density side, by removing the A port valve completely. Shots 31 and 32 were
good, with Ip around 460 kA, tons of x-rays and argon signals; #33 was a fizzle,
and again we increased the fill pressure up to 1.4e-5 for the last shot.

Conclusions: we had a very good run and feel very happy about our data, which
of course, now need to be analysed. ECE and PHA were also working fine, so
that we should be able to make interesting comparisons. Remarks: we didn't
need to inject an awful lot of argon to get a decent signal, and we can do with
less at low density, so you need not to be afraid to have argon when you run
your program!

Score of the day: 34 shots, 19 plasmas, 11 fizzles, 4 duds. Not bad!

Physics Operator Summaries

Session Leader Comments
Jul 29 1993 09:05:42:630AMFrancesca BombardaEngineering set up
Supply Start Close Open Crow bar Invert R (mOhm)
EF1 L -1.1 -0.94 0.0 0.07 0.5 80.4
EF1 U -1.1 -0.94 0.0 0.07 0.5 80.7
X OH1 -1.1 -0.85 0.0 0.10 0.5 44.9
X OH2_L -1.1 -0.65 0.0 0.12 0.5 8.4
X OH2_U -1.1 -0.65 0.0 0.12 0.5 8.5
EF2 L -0.4 0.5 46.0
EF2 U -0.4 0.5 45.5
EF3 -0.05 0.5
EF4 -1.1 0.5
EFC -0.02 0.5 150.
TF -1.65 0.55
X Bus diags Integrator Start: -2. Integrator End: 6.

Dig Time: -1.7 Dig Freq: 1500.00
Scope 0: -2.25 Scope 1: -3.2

Program of the day: Ti, Te profiles

Jul 29 1993 09:27:47:590AM930729001Francesca BombardaEngineering set up
Supply Start Close Open Crow bar Invert R (mOhm)
EF1 L -1.1 -0.94 0.0 0.07 0.5 80.4
EF1 U -1.1 -0.94 0.0 0.07 0.5 80.7
X OH1 -1.1 -0.85 0.0 0.10 0.5 44.9
X OH2_L -1.1 -0.65 0.0 0.12 0.5 8.4
X OH2_U -1.1 -0.65 0.0 0.12 0.5 8.5
EF2 L -0.4 0.5 46.0
EF2 U -0.4 0.5 45.5
Fizzle. Field pressure=1.2e-5

For shot #2 F.p=1.0e-5
from 50 to 250 msec OH1 from -100 to 50 V
OH2 from -10 to 0 V

Jul 29 1993 09:49:20:390AM930729002Francesca BombardaFizzle. Commutation failure in the EF1 power supply.

Jul 29 1993 10:03:02:100AM930729003Francesca BombardaFizzle.

For #4 , fill pressure up to 1.4e-5.

Jul 29 1993 10:37:23:610AM930729005Francesca BombardaEF2_U raised to 1750. A before commutation. Still a fizzle.
For #6 , turned on feedback control on Bradial from 0 to 50msec.

Jul 29 1993 10:49:37:860AM930729006Francesca BombardaFizzle.

For #7, fill pressure down to 1.0 e-5

Jul 29 1993 11:07:36:950AM930729007Francesca BombardaOK. Good argon spectra.
For #8, gas down to 8.5e-6

Jul 29 1993 11:19:28:670AM930729008Francesca BombardaOk . Even better spectra.
No changes.

Jul 29 1993 11:36:01:850AM930729009Francesca BombardaOK.
For #10, moved A port gas pulses forward in time by 30 msec.

Jul 29 1993 11:49:55:680AM930729010Francesca BombardaOk.
For #11, moved argon puff from +20 to -50 msec.
Increased chopper biased current, starting at 140 msec by increasing pre-programmed V.

Jul 29 1993 12:02:36:250PM930729011Francesca BombardaDud.

For #12, argon puff moved forward at 0. sec
Fill pressure 1.0e-5

Jul 29 1993 12:14:44:250PM930729012Francesca BombardaDud.
Fill down to 6.5-6 for next shot and argon off.

Jul 29 1993 12:31:19:430PM930729013Francesca BombardaDud.
Fill up to 1.2e-5 for next shot and argon off.

Jul 29 1993 12:44:03:080PM930729014Francesca Bombarda200 msec or so of plasma (300 kA). EF1_U trip
For #15, fill pressure set to 1.0e-5

Jul 29 1993 12:53:02:940PM930729015Francesca BombardaOK. No changes.

Jul 29 1993 01:09:32:380PM930729016Francesca BombardaFizzle. Fill pressure up to 1.2e-5 for next shot. Moved the A port
second gas puff closer to first

Jul 29 1993 01:31:15:410PM930729017Francesca BombardaOk.

Jul 29 1993 01:42:55:410PM930729018Francesca BombardaOK. NO changes

Jul 29 1993 02:00:15:680PM930729019Francesca BombardaOK. Increase length of last gas puff

Jul 29 1993 02:11:25:090PM930729020Francesca BombardaOk.
For #21, try to raise the density by an extra pulse at 40 ms.

Jul 29 1993 02:24:44:880PM930729021Francesca BombardaOk, but not very nice.
Made all pulses from A port shorter for next pulse.

Jul 29 1993 02:36:59:240PM930729022Francesca BombardaOk, nice shot, but density back to previous level. For #23, changed the gas waveform.
EFC control turned off at 350 msec.

Jul 29 1993 02:43:11:080PM930729023Francesca BombardaOk, nice shot, but density back to previous level. For #23, changed the gas waveform.
EFC control turned off at 350 msec.

Jul 29 1993 02:51:58:040PM930729023Francesca BombardaOK, but not a happy shot.
Small adjustements on the alternator (up to 13500 V)
For next shot , gas valve waveform changed.

Jul 29 1993 03:07:46:290PM930729024Francesca BombardaFizzle. But no change.

Jul 29 1993 03:16:47:420PM930729025Francesca BombardaOK, but ne still low. More changes for next shot.
EFC back on.

Jul 29 1993 03:37:31:680PM930729026Francesca BombardaToo much gas, Ip only makes it to 300 kA . No changes for next shot, but just wait
until methane level goes down (Marmar's theory)

Jul 29 1993 03:47:18:900PM930729027Francesca BombardaFizzle. No changes

Jul 29 1993 04:02:18:320PM930729028Francesca Bombarda OK, with some esitations. Density doesn't go any higher.
Argon puff returned to previous value.

Jul 29 1993 04:13:24:800PM930729029Francesca BombardaDud.

For #30, no gas from A port, raised fill pressure up to 1.3 e-5

Jul 29 1993 04:25:13:800PM930729030Francesca BombardaFizzle. No changes

Jul 29 1993 04:38:26:810PM930729031Francesca BombardaOk. Low density.
A valve was turned off by PLC, but the waveform is still there. Be aware!
No changes.

Jul 29 1993 04:57:28:120PM930729032Francesca BombardaOK. No changes.

Jul 29 1993 05:02:08:430PM930729033Francesca BombardaFizzle. Increase fill p. to 1.4e-5

Jul 29 1993 05:45:16:210PM930729034Francesca BombardaOK.

Physics Operator Comments

Engineering Operator Comments
ShotTimeTypeStatusComment
108:53:48:580AMPlasmaOkFizzle; EF3 bus voltage 2500
209:26:04:410AMPlasmaBadEF1 power supply commutation failure
309:50:27:830AMPlasmaOkFizzle
410:09:20:090AMPlasmaOkFizzle
510:25:06:170AMPlasmaOkFizzle
610:38:41:360AMPlasmaOkFizzle
710:51:15:310AMPlasmaOkPlasma!
811:04:53:460AMPlasmaOkPlasma
911:20:58:990AMPlasmaOkPlasma. Working to increase density earlier.
1011:36:09:310AMPlasmaOkPlasma. Sparks on TV
1111:51:15:410AMPlasmaOkno faults -- no plasma
1212:04:22:770PMPlasmaOkno faults -- no plasma
1312:16:47:220PMPlasmaOk
1412:29:50:350PMPlasmaBadEF1U Power Supply Commutation Failure
1512:44:16:780PMPlasmaOkAll OK. Nice Plasma. Nothing changed since last shot
1612:58:43:140PMPlasmaOkFizzle
1701:11:36:800PMPlasmaOkPlasma Back
1801:35:06:830PMPlasmaOkGood shot
1901:45:52:480PMPlasmaOkGood Plasma. EFCL warming up
2001:56:53:270PMPlasmaOkGood Shot
2102:13:45:220PMPlasmaOkGood Shot
2202:25:22:400PMPlasmaOkGood Shot
2302:39:22:120PMPlasmaOkVery disruptive Plasma.
2402:51:10:540PMPlasmaOkFizzle
2503:05:23:170PMPlasmaOkPlasma, 470 kA, not runaway
2603:19:17:100PMPlasmaOkPlasma with sparks showing on ALC-TV channel 34
2703:38:03:270PMPlasmaOkFizzle
2803:49:06:630PMPlasmaOkPlasma with interesting density bump
2904:02:54:780PMPlasmaOkDud. Flux plots look OK to me.
3004:15:39:170PMPlasmaOkFizzle
3104:27:20:780PMPlasmaOkPlasma. Discharge length over 530 msec. Low density, lots of x-rays.
3204:39:50:980PMPlasmaOkPlasma
3304:52:06:280PMPlasmaOkFizzle
3405:04:19:460PMPlasmaOkPlasma
3505:15:36:260PMTestOkTest of other OH1 6-pulse forward bridge