Alcator C-Mod Run 1021029 Information

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Miniproposals
Miniproposal:326
Date Filed: 8/26/2002
Title:D, E, and J-port Antenna Evaluation and Comparison
First Author:Steve Wukitch
Session Leader:Steve Wukitch (shots 1-8)

Operators
Session leader(s):Steve Wukitch
Physics operator(s):Joseph Snipes
Engineering operator(s):Gary Dekow,Bill Byford

Engineering Operator Run Comment
MP 326, RF antenna evaluation; SL: Wukitch; PO: Snipes; EO: Dekow/Byford

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:31:617PM
Author: To Be Determined
MP 326, RF antenna evaluation

Session leader: S. Wukitch
Physics operator: J. Snipes

Power Systems as on 1021004003 ensure fizzle detector set to 1.9 s

ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00.

Run begins at 09:00 and ends at 17:00.

Gas setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC)
fill C-side with 30 psi D2 Hybrid enabled (PG3)
leave J-Bottom as is Hybrid DISABLED (PG5)

Enable the following gate valve, assuming no vacuum problems: DNB

RF Setup: All 3 working transmitters should be operational by 9:00 am though
there may be a delay in the start of the run to finish the frequency retuning

Run Plan:
1) Verify J-port operation at 78MHz following the retuning
2) Evaluate the voltage standoff capability, particularly on D&E, but
also on J, in preparation for proposed modifications during the upcoming
vent. This will include operation with field but no gas and no plasma.
3) it may be possible to accomodate some MSE-related (calibration) shots by
puffing gas after the RF pulse is over on these non-plasma shots as well as
some Active MHD antenna RF pick-up tests.

Start with no gas TF shots at 4 - 5 T with a 600 ms flattop followed by
pulses with increasing amounts of gas but still no plasma. Also, accomodate
DNB tests with EF3/EF4 on top of the TF waveform as on 1021004003 but with the
time of the puff moved to 600ms and the flattop extended from 250ms to about
750ms.
-------------------------------------------------------------------------------
002 BT~5.4T, Ip~0.8 MA, nl04~0.9
D: 0.8 MW [0.8,1.5] sec
J: 0.4 MW [0.6,0.9] sec
result: plasma - EDA with D
D: 0.8 MW needs a better match
J: 0.4 MW max faults
003 BT~5.4T, Ip~0.8 MA, nl04~0.9
D: 1.0 MW [0.8,1.5] sec
J: 0.4 MW [0.6,0.9] sec
result: plasma - EDA with D
D: 1.0 MW faulting
J: 0.4 MW max faults
004 BT~5.4T, Ip~0.8 MA, nl04~0.9
D: 1.0 MW [0.8,1.5] sec
J: 0.4 MW [0.6,0.9] sec
result: plasma - EDA with D
D: 1.0 MW one fault
J: 0.4 MW max faults but ran a bit - need fudge factors!!!
005 BT~5.4T, Ip~0.8 MA, nl04~0.9
D: 1.0 MW [0.8,1.5] sec
J: 0.4 MW [0.6,0.9] sec
result: plasma - EDA with D
D: 1.0 MW one fault
J: 0.4 MW max faults but ran a bit
006 BT~5.4T, Ip~0.8 MA, nl04~0.9
D: 1.2 MW [0.8,1.5] sec
J: 0.4 MW [0.6,0.9] sec
result: plasma - EDA with D
D: 1.2 MW one fault
J: 0.4 MW max faults but ran a bit
007 BT~5.4T, Ip~0.9 MA, nl04~0.9
D: 1.4 MW [0.8,1.5] sec
J: 0.4 MW [0.6,0.9] sec
result: plasma - EDA with D
D: 1.4 MW 2 faults
J: 0.4 MW max faults - when it went into EDA
008 BT~5.4T, Ip~0.9 MA, nl04~0.9
D: 1.5 MW [0.8,1.5] sec
J: 0.75 MW [0.6,1.5] sec
result: plasma - EDA
D: 1.5 MW 5 faults
J: 0.9 MW clean

Summary

Although the run was brief, we accomplished the highest priority item
of verifying the operational status of J-port at 78 MHz. After
struggling to obtain a match, J-port operated up to 1 MW into an EDA
plasma. D-port also performed quite well obtaining 40 kV operation
for ~0.6 sec. This raises some questions as to why at other times the
voltage limit degrades to 30 kV.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:16:707PM
Author: To Be Determined
MP 326, RF antenna evaluation

Session leader: S. Wukitch
Physics operator: J. Snipes

Power Systems as on 1021004003 ensure fizzle detector set to 1.9 s

ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00.

Run begins at 09:00 and ends at 17:00.

Gas setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC)
fill C-side with 30 psi D2 Hybrid enabled (PG3)
leave J-Bottom as is Hybrid DISABLED (PG5)

Enable the following gate valve, assuming no vacuum problems: DNB

RF Setup: All 3 working transmitters should be operational by 9:00 am though
there may be a delay in the start of the run to finish the frequency retuning

Run Plan:
1) Verify J-port operation at 78MHz following the retuning
2) Evaluate the voltage standoff capability, particularly on D&E, but
also on J, in preparation for proposed modifications during the upcoming
vent. This will include operation with field but no gas and no plasma.
3) it may be possible to accomodate some MSE-related (calibration) shots by
puffing gas after the RF pulse is over on these non-plasma shots as well as
some Active MHD antenna RF pick-up tests.

Start with no gas TF shots at 4 - 5 T with a 600 ms flattop followed by
pulses with increasing amounts of gas but still no plasma. Also, accomodate
DNB tests with EF3/EF4 on top of the TF waveform as on 1021004003 but with the
time of the puff moved to 600ms and the flattop extended from 250ms to about
750ms.

Summary: There were long delays partly due to RF maintenance and partly due to
problems with the alternator that meant that the run did not start until after
3:00 pm. Nonetheless, except for a fizzle on the first shot apparently due to
a saturated input on the hybrid computer, all the other 7 shots were full
length discharges with ICRF EDA H-modes. Shot 8 had power from D and J3 and
produced a nice steady EDA for more than 0.75 s. More work is required to tune
up the RF, but this was a good start. Scorecard: 8 shots, 7 plasmas, 1 fizzle.

Run delayed for RF maintenance.
Run further delayed due to alternator problems.

Shot 1: Copied shot 1021025025 and maintained nl04 at 8 x 10^19 m^-2 up to
1.4 s. Fizzle!
Shot 2: Decreased prepuff by 4 ms to 25 ms duration. There was also a
saturated input on the hybrid computer from DIVBOLO1 that Wolfe
just disconnected after shot 1. Good shot.
Shot 3: Repeat. Good shot.
Shot 4: Raised prepuff by 2 ms to 27 ms duration. Good shot.
Shot 5: Repeat. Good shot.
Shot 6: Repeat. Good shot.
Shot 7: Repeat. Good shot.
Shot 8: Repeat. Good shot.

Session Leader Comments
Oct 29 2002 03:48:18:917PM1021029002Steve Wukitch002 BT~5.4T, Ip~0.8 MA, nl04~0.9
D: 0.8 MW [0.8,1.5] sec
J: 0.4 MW [0.6,0.9] sec
result: plasma - EDA with D
D: 0.8 MW needs a better match
J: 0.4 MW max faults
Oct 29 2002 04:03:50:360PM1021029003Steve Wukitch003 BT~5.4T, Ip~0.8 MA, nl04~0.9
D: 1.0 MW [0.8,1.5] sec
J: 0.4 MW [0.6,0.9] sec
result: plasma - EDA with D
D: 1.0 MW faulting
J: 0.4 MW max faults
Oct 29 2002 04:19:58:463PM1021029004Steve Wukitch004 BT~5.4T, Ip~0.8 MA, nl04~0.9
D: 1.0 MW [0.8,1.5] sec
J: 0.4 MW [0.6,0.9] sec
result: plasma - EDA with D
D: 1.0 MW one fault
J: 0.4 MW max faults but ran a bit
Oct 29 2002 04:38:49:760PM1021029005Steve Wukitch005 BT~5.4T, Ip~0.8 MA, nl04~0.9
D: 1.0 MW [0.8,1.5] sec
J: 0.4 MW [0.6,0.9] sec
result: plasma - EDA with D
D: 1.0 MW one fault
J: 0.4 MW max faults but ran a bit
Oct 29 2002 04:57:48:100PM1021029006Steve Wukitch006 BT~5.4T, Ip~0.8 MA, nl04~0.9
D: 1.2 MW [0.8,1.5] sec
J: 0.4 MW [0.6,0.9] sec
result: plasma - EDA with D
D: 1.2 MW one fault
J: 0.4 MW max faults but ran a bit
Oct 29 2002 04:58:32:353PM1021029007Steve Wukitch007 BT~5.4T, Ip~0.9 MA, nl04~0.9
D: 1.4 MW [0.8,1.5] sec
J: 0.4 MW [0.6,0.9] sec
result: plasma - EDA with D
D: 1.4 MW 2 faults
J: 0.4 MW max faults - when it went into EDA
Oct 30 2002 10:10:32:930AM1021029008Steve Wukitch008 BT~5.4T, Ip~0.9 MA, nl04~0.9
D: 1.5 MW [0.8,1.5] sec
J: 0.75 MW [0.6,1.5] sec
result: plasma
D: 1.5 MW 5 faults
J: 1.0 MW clean

Physics Operator Comments
Oct 29 2002 09:28:39:837AMJoseph SnipesRun delayed for RF maintenance.
Oct 29 2002 09:48:15:510AMJoseph SnipesMP 326, RF antenna evaluation

Session leader: S. Wukitch
Physics operator: J. Snipes

Power Systems as on 1021004003 ensure fizzle detector set to 1.9 s

ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00.

Run begins at 09:00 and ends at 17:00.

Gas setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC)
fill C-side with 30 psi D2 Hybrid enabled (PG3)
leave J-Bottom as is Hybrid DISABLED (PG5)

Enable the following gate valve, assuming no vacuum problems: DNB

RF Setup: All 3 working transmitters should be operational by 9:00 am though
there may be a delay in the start of the run to finish the frequency retuning

Run Plan:
1) Verify J-port operation at 78MHz following the retuning
2) Evaluate the voltage standoff capability, particularly on D&E, but
also on J, in preparation for proposed modifications during the upcoming
vent. This will include operation with field but no gas and no plasma.
3) it may be possible to accomodate some MSE-related (calibration) shots by
puffing gas after the RF pulse is over on these non-plasma shots as well as
some Active MHD antenna RF pick-up tests.

Start with no gas TF shots at 4 - 5 T with a 600 ms flattop followed by
pulses with increasing amounts of gas but still no plasma. Also, accomodate
DNB tests with EF3/EF4 on top of the TF waveform as on 1021004003 but with the
time of the puff moved to 600ms and the flattop extended from 250ms to about
750ms.

Oct 29 2002 11:06:45:920AMJoseph SnipesRun further delayed due to alternator problems.
Oct 29 2002 03:29:33:747PM1021029001Joseph SnipesShot 1: Copied shot 1021025025 and maintained nl04 at 8 x 10^19 m^-2 up to
1.4 s. Fizzle!
Oct 29 2002 03:43:00:393PM1021029002Joseph SnipesShot 2: Decreased prepuff by 4 ms to 25 ms duration. There was also a
saturated input on the hybrid computer from DIVBOLO1 that Wolfe
just disconnected after shot 1. Good shot.
Oct 29 2002 03:57:58:930PM1021029003Joseph SnipesShot 3: Repeat. Good shot.
Oct 29 2002 04:11:04:157PM1021029004Joseph SnipesShot 4: Raised prepuff by 2 ms to 27 ms duration. Good shot.
Oct 29 2002 04:28:06:620PM1021029005Joseph SnipesShot 5: Repeat. Good shot.
Oct 29 2002 04:42:32:343PM1021029006Joseph SnipesShot 6: Repeat. Good shot.
Oct 29 2002 05:03:43:533PM1021029007Joseph SnipesShot 7: Repeat. Good shot.
Oct 29 2002 05:04:00:690PM1021029008Joseph SnipesShot 8: Repeat. Good shot.
Oct 29 2002 05:15:42:347PM1021029008Joseph SnipesSummary: There were long delays partly due to RF maintenance and partly due to
problems with the alternator that meant that the run did not start until after
3:00 pm. Nonetheless, except for a fizzle on the first shot apparently due to
a saturated input on the hybrid computer, all the other 7 shots were full
length discharges with ICRF EDA H-modes. Shot 8 had power from D and J3 and
produced a nice steady EDA for more than 0.75 s. More work is required to tune
up the RF, but this was a good start. Scorecard: 8 shots, 7 plasmas, 1 fizzle.

Engineering Operator Comments
ShotTimeTypeStatusComment
103:26:52:913PMPlasmaOk
203:41:19:250PMPlasmaOk
303:55:49:397PMPlasmaOk
404:09:26:340PMPlasmaOk
504:22:15:937PMPlasmaOk
604:35:20:817PMPlasmaOk
704:48:21:167PMPlasmaOk
805:01:13:513PMPlasmaOk