Alcator C-Mod Run 1000503 Information

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Miniproposals
Miniproposal:268
Date Filed: 4/7/2000
Title:Conditioning of D-, E-, or J-Port ICRF Antenna
First Author:Gerd Schilling
Session Leader:Rejean Boivin (shots 1-23)

Operators
Session leader(s):Rejean Boivin
Physics operator(s):Dmitri Mossessian
Engineering operator(s):Bill Cochran

Engineering Operator Run Comment
MP#268 ICRF Commissioning. Boivin/Mossessian/Cochran.

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:23:053PM
Author: To Be Determined

Today's run will be devoted to commisionning
all 4 transmitters.

After boronization (monday) we vacuum conditioned all
antennas to voltage above 30kV. They all came up
to voltage/power relatively quickly.

Due to the small number of plasmas today
we only started to get serious power into
plasma. Some issues were raised regarding
flow of gas from the DNB before breakdown, see the
physics operator summary for more details.

XMTR 1 and 2 eventually made it to 1.5 MW,
first separately, then combined for a total
of 3.0 MW towards the end of the day. Since
the plasma made it to H-mode, further
tuning is required but lack time for it.

We turned on 3 and 4 for the last 3 shots,
and on the last 2, the pickup level was high
enough to trip EF4 again. However, the phase
feedback system was off, and so it will need
another culprit. "Power threshold" for
tripping seemed low on last shot. Will continue
troubleshooting tomorrow.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:10:460PM
Author: To Be Determined
Physop summary for 1000503:

Post-boronization recovery shots, RF conditioning of all antennas.

SL.Boivin
PO Mossessian
EO Cochran

Engineering setup:
-------------------
ECDC overnight in He, turn off 2 hours before run

Power system setup as on 1000421019

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid enabled
leave B-side upper as is Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bottom as is Hybrid DISABLED
____________________________________________________________________

Summary:

Main problems encountered during the run were due to the exsessive amount of gas fed into
the machine when DNB gate valve opens. During last run (Fryday, 04/28/00) it was found that
DNB supplies about 30% of the prepuff gas. Consequently, the pulse_gas4 was lowered to 19 msec.
Today we started with DNB gate valve closed and, after 3 succesfull shots and one fizzle, we've got a dud.
After that the prepuff was increased to 23 msec and then droped to 21 msec after next fizzle. When on shot 11
DNB valve was opened, series of fizzles followed, caused by excessive gas pressure at t=0. We lowered
prepuff every shot, and after 4 fizzles obtained plasma with 12 msec pulse_gas4.
Breakdown was not very reliable, out of 9 shots we had after the right prepuff was set, three were fizzles.
RF E and D transmitters provided up to 2 MW together, some H-modes were observed.
When J port antenna was turned on, EF4 power supply had problems.

23 shots
21 plasma attempts
10 plasmas
9 fizzles
2 duds

___________________________________________________________
Details:

1000503001 OH test. Problem with curcuit braker.
1000503002 Repaet OH test. This time OK
1000503003 Try for plasma. RF and DNB off.
Plasma to 1.9 sec.
1000503004 Turn RF 1&2 on. No PCS change.
Plasma. Disrupred at 0.66 sec. Killed by RF (0.6 MW) ?
1000503005 Try again. No PCS change
1000503005 Try again. No PCS change
Plasma,1.85 sec. Both transmitters on. Number 2 produced large injection,
but plasma survived
1000503006 No PCS change.
Fizzle. Late breakdown.
For next shot: lower Br offset to -0.0015 from -0.0005
1000503007 Dud. Bz looks too high.
For next shot: increased pulse_gas4 to 23 msec from 19 msec.
1000503008 mossessian PHYSICS_OPERATOR May 3 2000 11:39:22:640AM
Plasma. Large injection at .95 sec led to disruption at .99.
Slow current rise at the beginning.
1000503009 No PCS changes.
Fizzle. Slow current rise.
For next shot: decrease pulse_gas4 to 21 msec
1000503010 PLasma. Slightly faster current rise. Some ugly H-modes during RF1
FOr next shot: No PCS changes. DNB will be on.
1000503011 Fizzle. Late breakdown. Slow current rise - too much gas from DNB.
F-side pressure at t=0 is 0.095 instead of 0.065 last shot.
For next shot: drop pulse_gas4 to 18 msec.
1000503012 Fizzle. Late breakdown. Slow current rise - too much gas from DNB.
F-side pressure at t=0 is 0.085
Drop pulse_gas4 to 15 msec
1000503013 Fizzle. F-side pressure at t=0 is 0.075
Drop pulse_gas4 to 12 msec
1000503014 Fizzle. F-side pressure at t=0 back to shot 10 level.
Current rise OK. TRy again.
For next shot: no PCS changes
1000503016 Plasma. ELMy H-mode with 1.5 MW of transmitter 1.
DNB on.
No PCS changes for next shot.
1000503017 Fizzle.
1000503018 Dud. DNB gate valve was not open and we didn't have enough gas for breakdown.
No PCS changes for next shot.
1000503019 Plasma. DNB gate valve was open this time the startup was OK.
2 MW out of 1&2, and 0.4 MW from J.
NO PCS changes for next shot
1000503020 Fizzle.
No PCS changes for next shot.
1000503021 PLasma. H mode. Disruption at 1.06 sec - a problem with EF4 power supply
(caused by J port RF ?)
1000503022 J port will be ramped up slowly to see if there is a threshold
for the "EF4 effect".
Fizzle.
No PCS changes for next shot
1000503023 PLasma.
Disrupted at 1.1 sec due to J port/EF4 problem.
-

Session Leader Comments
May 3 2000 10:05:01:373AMRejean Boivin
Physics plan for 1000503

Resume operation for all 4 transmitters.


1) get plasma

2) Bring XMTR 1 and 2, first separately, then together
- compare D and E performance

3) Bring XMTR 3 and 4 as much as possible.
- document sources of noise if possible

4) Make small variations in
a) gaps
b) vertical position
c) density
verify operation and troubleshoot as needed.
May 3 2000 10:17:38:060AM1000503004Rejean Boivin shot 004

D at 0.6 MW, lost the plasma during that pulse.
E was supposed to fire afterwards.

May 3 2000 10:16:01:560AM1000503005Rejean Boivin shot 005

Both transmitters firing at 0.6 MW (D) and 0.5 MW (E).
Good shot. Increase power for next shot.
May 3 2000 11:48:03:907AM1000503008Rejean Boivin shot 008

Plasma disrupted after lots of injection (boil-off from E?)

XMTR1 (D) to 1.1 MW
XMTR2 (E) to 1.0 MW

go to 1.2 MW on next shot. Same waveform.
May 3 2000 12:14:02:793PM1000503010Rejean Boivin shot 010

D went to 1.4 MW and obtained H-mode.
E to 1.2 MW, and got very close to H-mode.

Next shot, tune D to H-mode, and E go up to 1.4 MW.

May 3 2000 01:50:04:140PM1000503015Rejean Boivinshot 015

D made it to H mode at 1.4 MW
E put it also to H-mode but was not tuned for H-mode.


Retune E and push to 1.5 MW on next shot.
May 3 2000 03:12:56:247PM1000503019Rejean Boivinshot 019

Plasma.

D and E are now overlapped, 2 MW total, H-mode

later J antenna fired, 0.5 MW total, needs tuning.

Next shot, tuned all 4. Increase power on all 4.

Physics Operator Comments
May 3 2000 09:22:09:747AMDmitri MossessianThe run will be post-boronization recovery shots, followed by RF conditioning of all antennas.

MP#268 ICRF Commissioning
SL.Boivin
PO Mossessian
EO Cochran

Engineering setup:
-------------------
ECDC overnight in He, turn off 2 hours before run

Power system setup as on 1000421019

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid enabled
leave B-side upper as is Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bottom as is Hybrid DISABLED



8:46 Load from 1000428022

Cold start OK

We'll start with OH test.
May 3 2000 09:16:15:590AM1000503001Dmitri MossessianOH test. Problem with curcuit braker.
May 3 2000 09:16:42:390AM1000503002Dmitri MossessianRepaet OH test. This time OK
May 3 2000 09:39:32:967AM1000503003Dmitri MossessianTry for plasma. RF and DNB off.

Plasma to 1.9 sec.
May 3 2000 10:00:07:407AM1000503004Dmitri MossessianTurn RF 1&2 on. No PCS change.

Plasma. Disrupred at 0.66 sec. Killed by RF (0.6 MW) ?
May 3 2000 10:00:35:047AM1000503005Dmitri MossessianTry again. No PCS change
May 3 2000 10:12:46:217AM1000503005Dmitri MossessianTry again. No PCS change

Plasma,1.85 sec. Both transmitters on. Number 2 produced large injection,
but plasma survived
May 3 2000 10:43:39:687AM1000503006Dmitri MossessianNo PCS change.

Fizzle. Late breakdown.

For next shot: lower Br offset to -0.0015 from -0.0005

May 3 2000 10:59:38:357AM1000503007Dmitri MossessianDud. Bz looks too high.

For next shot: increased pulse_gas4 to 23 msec from 19 msec.
May 3 2000 11:39:22:640AM1000503008Dmitri MossessianPlasma. Large injection at .95 sec led to disruption at .99.
Slow current rise at the beginning.
May 3 2000 11:55:49:950AM1000503009Dmitri MossessianNo PCS changes.

Fizzle. Slow current rise.
For next shot: decrease pulse_gas4 to 21 msec
May 3 2000 12:39:52:123PM1000503010Dmitri MossessianPLasma. Slightly faster current rise. Some ugly H-modes during RF1

FOr next shot: No PCS changes. DNB will be on.
May 3 2000 12:44:03:357PM1000503011Dmitri MossessianFizzle. Late breakdown. Slow current rise - too much gas from DNB.
F-side pressure at t=0 is 0.095 instead of 0.065 last shot.

For next shot: drop pulse_gas4 to 18 msec.
May 3 2000 12:52:49:890PM1000503012Dmitri MossessianFizzle. Late breakdown. Slow current rise - too much gas from DNB.
F-side pressure at t=0 is 0.085

Drop pulse_gas4 to 15 msec
May 3 2000 01:09:48:280PM1000503013Dmitri MossessianFizzle. F-side pressure at t=0 is 0.075

Drop pulse_gas4 to 12 msec
May 3 2000 01:32:14:140PM1000503014Dmitri MossessianFizzle. F-side pressure at t=0 back to shot 10 level.
Current rise OK. TRy again.

For next shot: no PCS changes
May 3 2000 02:07:37:543PM1000503016Dmitri MossessianPlasma. ELMy H-mode with 1.5 MW of transmitter 1.
DNB on.

No PCS changes for next shot.
May 3 2000 02:48:08:407PM1000503017Dmitri MossessianFizzle.
May 3 2000 02:47:33:840PM1000503018Dmitri MossessianDud. DNB gate valve was not open and we didn't have enough gas for breakdown.

No PCS changes for next shot.
May 3 2000 03:02:37:937PM1000503019Dmitri MossessianPlasma. DNB gate valve was open this time the startup was OK.
2 MW out of 1&2, and 0.4 MW from J.

NO PCS changes for next shot
May 3 2000 03:29:38:763PM1000503020Dmitri MossessianFizzle.

No PCS changes for next shot.
May 3 2000 03:56:16:840PM1000503021Dmitri MossessianPLasma. H mode. Disruption at 1.06 sec - a problem with EF4 power supply
(caused by J port RF ?)
May 3 2000 04:23:33:640PM1000503022Dmitri MossessianJ port will be ramped up slowly to see if there is a threshold
for the "EF4 effect".

Fizzle.

No PCS changes for next shot
May 3 2000 05:00:48:497PM1000503023Dmitri MossessianPLasma.
Disrupted at 1.1 sec due to J port/EF4 problem.

Engineering Operator Comments
ShotTimeTypeStatusComment
108:58:59:950AMTestBadPF Breaker opened before shot
209:12:36:950AMTestOkNo Faults
309:25:42:483AMPlasmaOkPLasma
409:46:33:640AMPlasmaOk
510:04:39:060AMPlasmaOk
610:26:58:560AMPlasmaOk
710:45:31:543AMPlasmaOk
811:28:14:793AMPlasmaOk
911:47:27:373AMPlasmaOk
1012:03:19:653PMPlasmaOk
1112:26:23:860PMPlasmaOk
1212:44:14:670PMPlasmaOk
1301:01:28:890PMPlasmaOk
1401:17:00:967PMPlasmaOk
1501:36:27:903PMPlasmaOk
1601:57:32:140PMPlasmaOk
1702:21:11:747PMPlasmaOk
1802:39:42:873PMPlasmaOk
1902:55:15:860PMPlasmaOk
2003:17:47:293PMPlasmaOk
2103:37:54:140PMPlasmaOk
2204:19:54:140PMPlasmaOk
2304:35:12:763PMPlasmaBadEF4 Type 1 Flt ( IOC)