Alcator C-Mod Run 990811 Information

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Miniproposals
Miniproposal:214
Date Filed: 1/5/1999
Title:D and E-port RF System Commissioning
First Author:Steve Wukitch
Session Leader:Steve Wukitch (shots 1-15)

Operators
Session leader(s):Steve Wukitch
Physics operator(s):Joseph Snipes
Engineering operator(s):Frank Silva

Engineering Operator Run Comment
MP #214 RF Conditioning/Snipes,Silva

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:37:08:053PM
Author: To Be Determined
Engineering setup for 9908011 RF Conditioning

Run will begin at 09:00.
Setup power supplies from shot 990806009 (1 MA, 5.4 T, flattop to 1.4 s)

Two hours of ECDC in D2 prior to run.

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid enabled
fill B-side upper with 6 psi of H2 Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bottom as is Hybrid DISABLED

The following gate valves should be enabled, assuming no vacuum problems:
ECE, VUV

A standard Tuesday morning OH test will be done for shot 1.
-------------------------------------------------------------------------------

Run Plan for 990811: MP 214 -- RF conditioning

Session leader: S. Wukitch
Engineer in charge: F. Silva
Physics operator: J. Snipes

Start by loading 990806009, a 1 MA, 5.4 T discharge. RF may require frequent
access to the power room to debug the new power feedback control circuit(s).

Summary

The machine ran very well today, though I was plagued with fizzles for some
unclear reason. The startup was not as robust as it has been the past few
runs. Except for the fizzles, all plasmas were full length standard 1 MA
plasmas with no disruptions until 1.8 sec at low current. The RF did not run
very well though. The run began late (10 am) for testing of the RF feedback
circuit. Then, we ran a number of ohmic shots while the RF group did more
tests out of plasma. Shots 7, 12, and 13 then had RF between 0.4 and 0.64 MW
from J4. There were some tests of the divertor flaps from shot 4 onward opening
at 0.9 s for the rest of the discharge. Brian and Sanjay also noticed the fast
scanning probe lighting up with carbon emission, though the total amount of
carbon coming from the probe was quite small.

Scorecard:

7 plasmas
6 fizzles
1 OH test
__________
14 shots

Shot 1: Standard Tuesday (on Wednesday) OH test. O.K.
Shot 2: Copied shot 990806009. Good shot ramped down below 200 kA past 1.85
sec. Almost a carbon copy of 990806009. Good reproducibility. No RF.
Shot 3: Repeat. Good shot. No RF.
Shot 4: Repeat with flappers opening at 0.9 sec and then remaining open
throughout the rest of the shot. Fizzle!
Shot 5: Reduced prepuff by 2 msec to 16 msec duration. Probably we did not
wait long enough between shots to pump out the neutrals. Good shot.
Shot 6: Repeat again with flappers opening at 0.9 sec. Good shot.
Shot 7: Repeat again with flappers opening at 0.9 sec and low RF power from
J4 from 0.7 - 0.9 sec. Good shot. Up to 0.4 MW of RF from J4.
Shot 8: Repeat with more RF power. Fizzle!
Shot 9: Lowered EF4 current from -1275 to -1290 A at breakdown. Fizzle!
Shot 10: Returned EF4 current to -1265 A and increased prepuff back to 18 msec
duration. Fizzle!
Shot 11: Reduced Br0 by 1 mT to 5 mT. Fizzle!
Shot 12: Reloaded shot 990811002. Good shot. RF up to 0.4 MW out of J4.
Shot 13: Repeat. Good shot. RF up to 0.64 MW on J4.
Shot 14: Repeat. Fizzle!

Session Leader Comments
Aug 11 1999 01:19:25:000PM990811007Steve Wukitch007 plasma
#4 faulting due to bad tune
ramped power from 50-450 kW

next shot: raise initial ramp power and repeat
Aug 11 1999 01:46:24:730PM990811012Steve Wukitch012 plasma
feedback responded properly to fast change in loading at 0.76 sec

next shot: raised RF power again with a ramp
Aug 11 1999 01:45:49:293PM990811013Steve Wukitch013 plasma
650 kW with low reflected power

next shot: need to do a couple of tests on FMIT#3 - it will take about
1/2 hour till next shot
raise ramp again and repeat

Physics Operator Comments
Aug 11 1999 08:13:59:670AMJoseph SnipesEngineering setup for 9908011 RF Conditioning

Run will begin at 09:00.
Setup power supplies from shot 990806009 (1 MA, 5.4 T, flattop to 1.4 s)

Two hours of ECDC in D2 prior to run.

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid enabled
fill B-side upper with 6 psi of H2 Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bottom as is Hybrid DISABLED

The following gate valves should be enabled, assuming no vacuum problems:
ECE, VUV

A standard Tuesday morning OH test will be done for shot 1.
-------------------------------------------------------------------------------

Run Plan for 990811: MP 214 -- RF conditioning

Session leader: S. Wukitch
Engineer in charge: F. Silva
Physics operator: J. Snipes

Start by loading 990806009, a 1 MA, 5.4 T discharge. RF may require frequent
access to the power room to debug the new power feedback control circuit(s).


Aug 11 1999 10:10:58:687AM990811001Joseph SnipesShot 1: Standard Tuesday (on Wednesday) OH test. O.K.
Aug 11 1999 10:27:58:280AM990811002Joseph SnipesShot 2: Copied shot 990806009. Good shot ramped down below 200 kA past 1.85
sec. Almost a carbon copy of 990806009. Good reproducibility. No RF.
Aug 11 1999 10:34:42:200AM990811002Joseph SnipesBrief delay before shot 3 for power room access for the RF group.

Aug 11 1999 10:53:20:560AM990811003Joseph SnipesShot 3: Repeat. Good shot. No RF.
Aug 11 1999 11:08:39:420AM990811004Joseph SnipesShot 4: Repeat with flappers opening at 0.9 sec and then remaining open
throughout the rest of the shot. Fizzle!
Aug 11 1999 11:16:37:060AM990811005Joseph SnipesShot 5: Reduced prepuff by 2 msec to 16 msec duration. Probably we did not
wait long enough between shots to pump out the neutrals. Good shot.
Aug 11 1999 11:34:29:590AM990811005Joseph SnipesBrief delay for RF group to sort out a transmitter oscillation.
Aug 11 1999 11:49:34:233AM990811006Joseph SnipesShot 6: Repeat again with flappers opening at 0.9 sec. Good shot.
Aug 11 1999 12:17:02:403PM990811007Joseph SnipesShot 7: Repeat again with flappers opening at 0.9 sec and low RF power from
J4 from 0.7 - 0.9 sec. Good shot. Up to 0.4 MW of RF from J4.
Aug 11 1999 12:25:41:060PM990811008Joseph SnipesShot 8: Repeat with more RF power. Fizzle!
Aug 11 1999 12:40:05:230PM990811009Joseph SnipesShot 9: Lowered EF4 current from -1275 to -1290 A at breakdown. Fizzle!
Aug 11 1999 12:56:58:700PM990811010Joseph SnipesShot 10: Returned EF4 current to -1265 A and increased prepuff back to 18 msec
duration. Fizzle!
Aug 11 1999 01:11:36:107PM990811011Joseph SnipesShot 11: Reduced Br0 by 1 mT to 5 mT. Fizzle!
Aug 11 1999 01:25:16:530PM990811012Joseph SnipesShot 12: Reloaded shot 990811002. Good shot. RF up to 0.4 MW out of J4.
Aug 11 1999 01:43:30:280PM990811013Joseph SnipesShot 13: Repeat. Good shot. RF up to 0.64 MW on J4.
Aug 11 1999 02:09:45:607PM990811014Joseph SnipesShot 14: Repeat. Fizzle! Perhaps need more negative vertical field.
Aug 11 1999 02:20:08:500PM990811014Joseph SnipesSummary

The machine ran very well today, though I was plagued with fizzles for some
unclear reason. The startup was not as robust as it has been the past few
runs. Except for the fizzles, all plasmas were full length standard 1 MA
plasmas with no disruptions until 1.8 sec at low current. The RF did not run
very well though. The run began late (10 am) for testing of the RF feedback
circuit. Then, we ran a number of ohmic shots while the RF group did more tests
out of plasma. Shots 7, 12, and 13 then had RF between 0.4 and 0.64 MW from J4.
There were some tests of the divertor flaps from shot 4 onward opening at 0.9 s
for the rest of the discharge. Brian and Sanjay also noticed the fast scanning
probe lighting up with carbon emission, though the total amount of carbon
coming from the probe was quite small.

Scorecard:

7 plasmas
6 fizzles
1 OH test
__________
14 shots
Aug 11 1999 02:23:28:980PM990811014Joseph SnipesNote that the run was ended early for further RF work offline.

Engineering Operator Comments
ShotTimeTypeStatusComment
110:08:15:653AMTestOkOHs 10Ka Test
210:19:08:840AMPlasmaOkno faults
310:44:15:653AMPlasmaOkno faults
411:02:13:357AMPlasmaOkno faults
511:15:06:513AMPlasmaOk(null)
611:47:54:217AMPlasmaOk(null)
712:04:49:187PMPlasmaOk(null)
812:24:05:607PMPlasmaOk(null)
912:38:14:873PMPlasmaOk(null)
1012:51:30:153PMPlasmaOk(null)
1101:05:52:140PMPlasmaOk(null)
1201:19:37:250PMPlasmaOkno faults
1301:38:26:560PMPlasmaOk(null)
1401:58:18:763PMPlasmaOk(null)
1509:06:15:043AMTestBad