Alcator C-Mod Run 990805 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 1-10)
Session Leader:Rejean Boivin (shots 1-10)

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

Engineering Operator Run Comment
MP #214 R.F. Conditioning/Snipe, Silva

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:37:07:990PM
Author: To Be Determined
Session Leader: Boivin/Wukitch
Physics Operator: Snipes
Engineer in Charge: Silva

Engineering Setup for Thursday, 990805:

Run is scheduled to begin at 8:00 AM
Power supplies as on 990804010

Overnight ECDC in D2 prior to run. Stop 2 hours before start of 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

-------------------------------------------------------------------------------
Run Plan for 990805: MP 214 -- RF conditioning

Standard plasmas at 1 MA, 5.4 T, nl04 = 1.1 x 10^20 m^-2.
Start by loading 990804010.

There is a slight delay in the run to fix the door between Albany Street and
the power room.

Summary:
The machine ran very well today. There were 10 shots and they all had good
long 1 MA plasmas well into the rampdown. Some good pre-boronization data
was obtained for the edge group. The RF still needs some attention to get more
than 1 MW. Still, there were several dithering plasmas where it is clear that
the RF is now heating and we were near the H-mode threshold with less than 1 MW
of RF power. The H/(H+D) ratio was down to between 5 and 10% today
allowing decent heating. We intend to boronize tonight. Shots 990805001 and
990805009 were ohmic "fiducials" for pre- and post-boronization comparison of
impurities. For future reference, use shot 990805001 for fiducials since it
had a better rampdown.

Shot 1: Loaded shot 990804010. Starting pressure is down to 8.5 x 10^-8 Torr!
But, by the time of the shot, the pressure was up to 1.3 x 10^-7 Torr!
Good shot!
Shot 2: Repeat with stepping ramp up in E port RF power to check Moly source.
Good shot. Three steps up to 0.8 MW, though the third step was ratty.
Shot 3: Repeat attempting to improve the RF steps. Good shot. RF up to 1 MW
out of E port, though the third step is still ratty.
Shot 4: Repeat with shorter RF pulse. Spectroscopists doing a pre-boronization
survey of the impurities. Good shot. RF pulse still not well tuned.
Shot 5: Repeat with better RF tuning and reversing the steps in the RF power.
Good shot. Still RF not reaching 1 MW.
Shot 6: Playing with the rampdown after 1.6 sec to see if it may be possible
to rampdown even further by keeping the strike point from crossing the
inner nose, which may be burning away hydrogen and causing detachment
around 1.7 sec in the previous shots. Attempt to improve RF tuning
again. Good shot. Rampdown to 1.8 sec, but the detachment came
earlier and the EF2's went to zero current earlier. RF same as 5.
Shot 7: Moved RCUR further in after 1.5 sec to try to improve the rampdown
again. Added some D port power in addition to E port. Good shot.
Reached the desired 1 MW of RF. Rampdown is definitely worse.
Shot 8: Reloaded shot 990805005 before I started playing with the rampdown.
Then, I moved the ZXL up and ZXU down by 10 cm during the rampdown to
see if that helps. Rampdown is slightly worse disrupting at 1.77 sec.
RF up to 1 MW. Good shot.
Shot 9: Trying again to improve the rampdown by reducing the elongation even
more during the rampdown. Also keeping RCUR and CLEARIN out further
during the rampdown. No RF for this shot. Rampdown is worse.
Good shot.
Shot 10: Reloading 990805005 before the changes in the rampdown. This will be
the last shot to do RF maintenance. RF back on. Good shot. RF
triangle pulse to 1 MW. Rampdown returned to more than 1.8 sec.

Session Leader Comments
Aug 5 1999 10:16:41:670AMRejean Boivin
Transmitters 3 and 4 need serious work/careful
analysis. We will not run them in plasma today.

Before shutting down, we will run a few shots
to document pre-boronization conditions.

1) ohmic shot for R. Nachtrieb (Omegatron)
2) A series of Rf discharges with E only (maybe some
D later) to document Moly sources.
Aug 5 1999 10:17:13:607AM990805001Rejean Boivin
Shot 001

Ohmic only for the Omegatron.
Good long pulse.
Aug 5 1999 10:18:08:403AM990805002Rejean Boivin
Shot 002

Steps for the RF from E antenna.

Demand should 300 ms, 3 steps, 0.3 MW increment.

Results: not quite what we requested but pretty good
nonetheless
Aug 5 1999 10:20:48:137AM990805003Rejean Boivin
Shot 003

Steps for the RF from E antenna.

Demand should 300 ms, 3 steps, 0.3 MW increment.

Results: slightly better, a bit more power.
Aug 5 1999 10:19:11:730AM990805004Rejean Boivin
Shot 004

Steps for the RF from E antenna.

Demand should 500 ms, 2 steps, 0.5 MW increment.

Results: tuning getting better.
Aug 5 1999 10:20:27:857AM990805005Rejean Boivin
Shot 005

Steps for the RF from E antenna.

Demand should 500 ms, 2 steps, 0.5 MW increment.
Reverse steps to get the higher power pulse first.

Results: tuning getting better, not quite the 1 MW level.
Aug 5 1999 10:54:34:700AM990805006Rejean Boivin
Shot 006

Steps for the RF from E antenna.

Demand should 500 ms, 2 steps, 0.5 MW increment.


Results: tuning getting better, 0.8 MW level.
Aug 5 1999 10:55:01:280AM990805007Rejean Boivin
Shot 007

Steps for the RF from E antenna.

Demand should 500 ms, 2 steps, 0.5 MW increment.
Add D antenna as a "background", not much power out of tune.

Results: tuning getting better, 0.8 MW level.
Aug 5 1999 11:28:53:653AM990805008Rejean Boivin
Shot 008

Steps for the RF from E antenna.

Demand should 500 ms, 2 steps, 0.5 MW increment.
Add D antenna as a "background", not much power, still out of tune.

Aug 5 1999 11:29:11:187AM990805009Rejean Boivin
Shot 009

Ohmic shot for the omegatron.
Aug 5 1999 11:46:53:840AM990805010Rejean Boivin
Shot 010

Ramps (up and down) for internal
calibration of D and E antennas.

Shutting down for working on 3 and 4.

Physics Operator Comments
Aug 5 1999 08:03:58:187AMJoseph SnipesEngineering Setup for Thursday, 990805:

Run is scheduled to begin at 8:00 AM
Power supplies as on 990804010

Overnight ECDC in D2 prior to run. Stop 2 hours before start of 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
-------------------------------------------------------------------------------
Run Plan for 990805: MP 214 -- RF conditioning

Standard plasmas at 1 MA, 5.4 T, nl04 = 1.1 x 10^20 m^-2.
Start by loading 990804010.
Aug 5 1999 08:46:56:280AM990805001Joseph SnipesThere is a slight delay in the run to fix the door between Albany Street and
the power room.

Shot 1: Loaded shot 990804010. Starting pressure is down to 8.5 x 10^-8 Torr!
But, by the time of the shot, the pressure was up to 1.3 x 10^-7 Torr!
Good shot!
Aug 5 1999 09:06:34:780AM990805002Joseph SnipesShot 2: Repeat with stepping ramp up in E port RF power to check Moly source.
Good shot. Three steps up to 0.8 MW, though the third step was ratty.
Aug 5 1999 09:26:57:810AM990805003Joseph SnipesShot 3: Repeat attempting to improve the RF steps. Good shot. RF up to 1 MW
out of E port, though the third step is still ratty.
Aug 5 1999 09:47:35:827AM990805004Joseph SnipesShot 4: Repeat with shorter RF pulse. Spectroscopists doing a pre-boronization
survey of the impurities. Good shot. RF pulse still not well tuned.
Aug 5 1999 10:12:19:280AM990805005Joseph SnipesShot 5: Repeat with better RF tuning and reversing the steps in the RF power.
Good shot. Still RF not reaching 1 MW.
Aug 5 1999 10:41:58:263AM990805007Joseph SnipesShot 6: Playing with the rampdown after 1.6 sec to see if it may be possible
to rampdown even further by keeping the strike point from crossing the
inner nose, which may be burning away hydrogen and causing detachment
around 1.7 sec in the previous shots. Attempt to improve RF tuning
again. Good shot. Rampdown to 1.8 sec, but the detachment came
earlier and the EF2's went to zero current earlier. RF same as 5.
Aug 5 1999 10:51:39:480AM990805007Joseph SnipesShot 7: Moved RCUR further in after 1.5 sec to try to improve the rampdown
again. Added some D port power in addition to E port. Good shot.
Reached the desired 1 MW of RF. Rampdown is definitely worse.
Aug 5 1999 11:15:41:810AM990805008Joseph SnipesShot 8: Reloaded shot 990805005 before I started playing with the rampdown.
Then, I moved the ZXL up and ZXU down by 10 cm during the rampdown to
see if that helps. Rampdown is slightly worse disrupting at 1.77 sec.
RF up to 1 MW. Good shot.
Aug 5 1999 11:21:26:340AM990805009Joseph SnipesShot 9: Trying again to improve the rampdown by reducing the elongation even
more during the rampdown. Also keeping RCUR and CLEARIN out further
during the rampdown. No RF for this shot. Rampdown is worse.
Good shot.
Aug 5 1999 12:03:24:670PM990805010Joseph SnipesShot 10: Reloading 990805005 before the changes in the rampdown. This will be
the last shot to do RF maintenance. RF back on. Good shot. RF
triangle pulse to 1 MW. Rampdown returned to more than 1.8 sec.
Aug 5 1999 12:12:13:857PM990805010Joseph SnipesSummary:
The machine ran very well today. There were 10 shots and they all had good
long 1 MA plasmas well into the rampdown. Some good pre-boronization data
was obtained for the edge group. The RF still needs some attention to get more
than 1 MW. Still, there were several dithering plasmas where it is clear that
the RF is now heating and we were near the H-mode threshold with less than 1 MW
of RF power. The H/(H+D) ratio was down to between 5 and 10% today
allowing decent heating. We intend to boronize tonight. Shots 990805001 and
990805009 were ohmic "fiducials" for pre- and post-boronization comparison of
impurities. For future reference, use shot 990805001 for fiducials since it had
a better rampdown.

Engineering Operator Comments
ShotTimeTypeStatusComment
108:43:51:577AMPlasmaOkno faults
209:00:44:187AMPlasmaOkno faults
309:21:40:623AMPlasmaOkno faults
409:42:20:513AMPlasmaOkno faults
510:03:44:717AMPlasmaOkno faults
610:22:14:513AMPlasmaOkno faults
710:41:18:467AMPlasmaOkno faults
811:00:25:840AMPlasmaOkno faults
911:18:39:263AMPlasmaOkno faults
1011:37:31:810AMPlasmaOkno faults