Alcator C-Mod Run 1031021 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader: Unknown (shots 1-22)

Operators
Session leader(s): Unknown
Physics operator(s):Joseph Snipes
Engineering operator(s): Unknown

Engineering Operator Run Comment
Plasma Startup and Conditioning

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:37:19:397PM
Author: Joseph Snipes
Engineering setup for Tuesday, 21 Oct 2003


Purpose: Plasma startup and conditioning

Session leader: --
Physics operator: J. Snipes Engineering operator:
ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00.
Bake at 60 C overnight as well.

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

Power systems the same as on 1031016029 (0.8 MA, 5.4 T, lower single null)

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

Enable the following gate valves, assuming no vacuum problems:
ECE, VUV, DNB


-------------------------------------------------------------------------------
RF Setup: Transmitters 1, 2, 3 and 4 in RUN ON by 08:00 am


-------------------------------------------------------------------------------
Run Plan: We'll continue running cleanup plasmas while monitoring H/D,
etc. RF Group will condition J, D & E at 78 MHz, 80 and 80.5 MHz.

Summary: The run went pretty well up to shot 14. The first shot was a test of the A-coil
supply and the shots after 14 were more A-coil test shots. Shot 2 disrupted at 0.6 s
following a large injection. Then, after a few minutes ECDC, the plasmas ran full length
until shot 13 which fizzled. Shot 14 was also a full length plasma after a few minutes
of ECDC, though the density increased too rapidly particularly after the NINJA injected
still more than the programmed gas. After shot 14, it was decided to cancel the run
because the helium purity in the alternator dropped below 84% indicating a problem
with the alternator. Work will resume on the alternator today and we will hopefully run
tomorrow.

Scorecard up to shot 14: 1 test
1 fizzle
12 plasmas

Shot 1: Started with what was in the model from 1031017032, which was a lower
single null plasma. Modified the A-coil waveform to start at 0.25 s
ramp up to 3000 A at 0.5 s then ramp down at 1 s to zero at 1.25 s for
tests of the A-coil supply. No plasma A-coil test. A-coil still has
a large offset and the current is down by a factor of two over the request.
Shot 2: Started with 20 min of ECDC in D2 to recover from RF conditioning before
the run while work was being done on the A-coil supply. Alternator heater trip
made the alternator slow down just before the shot causing a small delay
while it spins up to speed again. Plasma shot disrupted at 0.605 s. Big
injection at 0.56 s. NINJA set to 90 psi of He.
Shot 3: 5 min ECDC after the disruption. Good shot.
Shot 4: Repeat. Good shot. Got a brief H-mode from 0.87 - 0.94 s with 1.5 MW of RF.
Shot 5: Repeat. NINJA He puff around 1 s. Good shot disrupted at 1.58 s. H/H+D ~ 0.09.
Shot 6: Repeat. Good shot. Brief H-mode from 0.78 - 0.85 s.
Shot 7: Reduce nl04 to 0.8 x 10^20 m^-2 at Bruce's request. Good shot. Did not get the
requested density though.
Shot 8: Try reducing the density to 0.7 x 10^20 m^-2. Reduce NINJA to 45 psi of He.
Good shot. No H-mode despite 2.2 MW of RF.
Shot 9: Repeat. Good shot. H/(H+D) ~ 0.12. No H-mode.
Shot 10: Repeat. Good shot.
Shot 11: Return to nl04 = 1 x 10^20 m^-2. Good shot. Got the H-mode back with 2.5 MW of RF.
Shot 12: IGOR hold up before this shot. Raised nl04 to 1.2 x 10^20 m^-2 Good shot. No H-mode.
Shot 13: Raised nl04 to 1.4 x 10^20 m^-2. Fizzle!
Shot 14: ECDC for 8 min. Then repeat. Good shot but the density behaved badly for some
reason and so did the plasma current. Apparently, I asked the density to rise
too quickly, but then it kept going beyond the request. Alternator problems
after the shot will cause a delay so we will run A-coil test shots in the meantime.

Session Leader Comments

Physics Operator Comments
Oct 21 2003 11:58:01:780AMJoseph SnipesEngineering setup for Tuesday, 21 Oct 2003


Purpose: Plasma startup and conditioning

Session leader: --
Physics operator: J. Snipes Engineering operator:
ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00.
Bake at 60 C overnight as well.

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

Power systems the same as on 1031016029 (0.8 MA, 5.4 T, lower single null)

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

Enable the following gate valves, assuming no vacuum problems:
ECE, VUV, DNB


-------------------------------------------------------------------------------
RF Setup: Transmitters 1, 2, 3 and 4 in RUN ON by 08:00 am


-------------------------------------------------------------------------------
Run Plan: We'll continue running cleanup plasmas while monitoring H/D,
etc. RF Group will condition J, D & E at 78 MHz, 80 and 80.5 MHz.
Oct 21 2003 11:58:32:047AM1031021001Joseph SnipesShot 1: Started with what was in the model from 1031017032, which was a lower
single null plasma. Modified the A-coil waveform to start at 0.25 s
ramp up to 3000 A at 0.5 s then ramp down at 1 s to zero at 1.25 s for
tests of the A-coil supply. No plasma A-coil test. A-coil still has
a large offset and the current is down by a factor of two over the request.
Oct 21 2003 11:58:52:530AM1031021002Joseph SnipesShot 2: Started with 20 min of ECDC in D2 to recover from RF conditioning before
the run while work was being done on the A-coil supply. Alternator heater trip
made the alternator slow down just before the shot causing a small delay
while it spins up to speed again. Plasma shot disrupted at 0.605 s. Big
injection at 0.56 s. NINJA set to 90 psi of He.
Oct 21 2003 11:59:03:920AM1031021003Joseph SnipesShot 3: 5 min ECDC after the disruption. Good shot.
Oct 21 2003 11:59:18:110AM1031021004Joseph SnipesShot 4: Repeat. Good shot. Got a brief H-mode from 0.87 - 0.94 s with 1.5 MW of RF.
Oct 21 2003 11:59:29:703AM1031021005Joseph SnipesShot 5: Repeat. NINJA He puff around 1 s. Good shot disrupted at 1.58 s. H/H+D ~ 0.09.
Oct 21 2003 11:59:47:937AM1031021006Joseph SnipesShot 6: Repeat. Good shot. Brief H-mode from 0.78 - 0.85 s.
Oct 21 2003 12:00:04:907PM1031021007Joseph SnipesShot 7: Reduce nl04 to 0.8 x 10^20 m^-2 at Bruce's request. Good shot. Did not get the
requested density though.
Oct 21 2003 12:00:16:077PM1031021008Joseph SnipesShot 8: Try reducing the density to 0.7 x 10^20 m^-2. Reduce NINJA to 45 psi of He.
Good shot. No H-mode despite 2.2 MW of RF.
Oct 21 2003 12:00:29:640PM1031021009Joseph SnipesShot 9: Repeat. Good shot. H/(H+D) ~ 0.12. No H-mode.
Oct 21 2003 12:00:43:423PM1031021010Joseph SnipesShot 10: Repeat. Good shot.
Oct 21 2003 12:16:51:577PM1031021011Joseph SnipesShot 11: Return to nl04 = 1 x 10^20 m^-2. Good shot. Got the H-mode back with 2.5 MW of RF.
Oct 21 2003 12:54:02:157PM1031021012Joseph SnipesShot 12: IGOR hold up before this shot. Raised nl04 to 1.2 x 10^20 m^-2.
Good shot. No H-mode.
Oct 21 2003 12:59:04:687PM1031021013Joseph SnipesShot 13: Raised nl04 to 1.4 x 10^20 m^-2. Fizzle!
Oct 21 2003 01:30:31:093PM1031021014Joseph SnipesShot 14: ECDC for 8 min. Then repeat. Good shot but the density behaved badly for some
reason and so did the plasma current. Apparently, I asked the density to rise
too quickly, but then it kept going beyond the request. Alternator problems
after the shot will cause a delay so we will run A-coil test shots in the meantime.
Oct 21 2003 02:48:43:780PM1031021014Joseph SnipesSummary: The run went pretty well up to shot 14. The first shot was a test of the A-coil
supply and the shots after 14 were more A-coil test shots. Shot 2 disrupted at 0.6 s
following a large injection. Then, after a few minutes ECDC, the plasmas ran full length
until shot 13 which fizzled. Shot 14 was also a full length plasma after a few minutes
of ECDC, though the density increased too rapidly particularly after the NINJA injected
still more than the programmed gas. After shot 14, it was decided to cancel the run
because the helium purity in the alternator dropped below 84% indicating a problem
with the alternator. Work will resume on the alternator today and we will hopefully run
tomorrow.

Scorecard up to shot 14: 1 test
1 fizzle
12 plasmas

Engineering Operator Comments
ShotTimeTypeStatusComment
108:43:44:340AMTestOkCorrection Coil Test
209:34:48:360AMPlasmaOk
309:57:41:610AMPlasmaOk
410:11:13:030AMPlasmaOk
510:24:56:877AMPlasmaOk
610:40:59:687AMPlasmaOk
710:56:22:720AMPlasmaOk
811:16:08:123AMPlasmaOk
911:31:13:763AMPlasmaOk
1011:51:24:437AMPlasmaOk
1112:04:38:890PMPlasmaOk
1212:42:00:470PMPlasmaOk
1312:55:28:610PMPlasmaOk
1401:19:37:310PMPlasmaOk
1501:45:37:157PMTestOkCC_M-S test
1602:12:43:170PMTestOk
1702:42:54:000PMTestOk
1803:09:58:330PMTestOk
1903:35:58:013PMTestOk
2003:46:20:580PMTestOk
2104:11:27:877PMTestOk
2204:22:46:983PMTestOk