Alcator C-Mod Run 1060419 Information

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Miniproposals
Miniproposal:443
Date Filed:11/28/2005
Title:Temperature scale length measurements using Btor sweeps
First Author:P. Phillips
Session Leader:P. Phillips (shots 1-28)

Operators
Session leader(s):P. Phillips
Physics operator(s):Earl Marmar
Engineering operator(s):Ed Fitzgerald,Gary Dekow

Engineering Operator Run Comment
MP# 404A TAE Dampening with ICRF EO Pierson PO Marmar SL Snipes

Session Leader Plans
Entered: Apr 18 2006 05:14:12:507PM
Author: Joseph Snipes
Run Plan for MP#404a TAE Damping with ICRF

Begin with 1060309020 inner wall limited moderate elongation plasmas with
nl04 = 9 x 10^19 m^-2, Ip = 0.8 MA, and BT = 5.4 T. Reduce nl04 to 7 x 10^19 m^-2.
Sweep the active MHD antennas through the calculated center of the gap TAE frequency
multiple times throughout the discharge and look for resonances. From shot to shot
slowly increase the ICRF power in steps of 0.25 MW from 0.5 to 1.5 s up
to 2.5 MW or until unstable TAEs are observed. Measure the TAE damping
rate for each ICRF power level. Only D and E ICRF antennas will be required.
Phasing of the active MHD antennas will also be changed between shots to
compare in phase and out of phase operation as well as with a single antenna
alone. Each phase change requires a cell access.
Entered: Apr 19 2006 12:33:35:100PM
Author: P. Phillips
MP443 LTe using BT sweeps
BT=5.2, 0.6MA, 1x10^20
Vary RF power from 200kw to Max avialable with BT ramps before and during.
BT ramp 0.08T increase at .8s and ramped back at 1.2

Physics Operators Plans
Entered: Apr 19 2006 09:02:09:317AM
Author: Earl Marmar
Physop Plan and engineering setup for Wednesday, April 19, 2006

MP 443 Temperature scale length measurements using Btor sweeps

PO: Marmar
SL: P. Phillips

This MP will be run if the FRCECE system is working after recent repairs. If not, MP404A, Parametric Dependence of Moderate n Alfven Eigenmode Damping Rates with ICRF, is the backup (SL: Snipes).

Recent repairs to the J-port ICRF antenna will also be tested.

no overnight ECDC

Power systems as on 1060414001 (LSN, 800 kA).
A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and enabled.
C-coil Start=0.3sec, Invert=2.0sec

D, E and J (1-4) ICRF systems in run-on by 8:30 am.

Gas Setup:
----------
fill B-top 6psi D2 Hybrid enabled (PG4)
fill B-side lower 1 psi Argon Hybrid Disabled (PG1)
leave B-side Upper as is, Hybrid Disabled (PG2)
fill B-main 40psi D2 Hybrid Enabled (PG3)



-------------------------------------------------------------------------------
ICRF Setup: We'll need ICRF starting at 200 kW, increasing shot by shot up to a total of 3 MW, if available.
------------------------------------------------------------------

After establishing that the FRCECE system is working, we will lower the current to 600 kA, and add small TF sweeps.

If we switch to MP404A, we will run inner wall limited discharges, with RF powers up to 2.5 MW.

Session Leader Summaries
Entered: Apr 19 2006 05:10:27:943PM
Author: P. Phillips
MP443 - we should have completed this MP. Data was very good with sawteeth at very high frequency so they should not be a limit on data analysis. The biggest limitation will be constant conditions during ramp down in RF. RF power from 200kW to 3.5MW covered.
Shot summary
5 - 200kW, 7,8 500kW, 9,10 1MW, 11,18 1.5MW, 19,22 2MW, 23,24 2.5MW, 25, 26 3MW, 28 3.5MW.

Physics Operator Summaries
Entered: Apr 19 2006 05:29:33:007PM
Author: Earl Marmar
This was a straightforward run from the physop point of view. The only change to the startup was to tweak the fill pressure prepuff, attempting to chase the base pressure just before a shot, which varies with time between pulses, and after disruptions. It is not clear that this had any effect. Some shots had early runaways.

The sparker was giving smooth current time histories, with about 2 mA just before t=0.

Two shots (19 and 21) disrupted early, around the time of crossover, before RF. After lowering the target nl_04 from 8e19 to 7e19, this did not recur.

About 2.5 hours were lost during the middle of the run because of an EF3 problem. On shot 12, EF3 did not turn on until after t=+6 seconds. The cause was never definitively determined, and the problem did not recur.



Scorecard:

plasmas: 22
fizzles: 0
dud (no EF3): 1
tests: 5

total cycles: 28

Session Leader Comments
Apr 19 2006 10:12:15:863AM1060419005P. PhillipsStart of MP443: Use Bt ramps to measure LTe. Ramp up Bt (5.2T) 0.08T before RF and then back down during RF. Start at 200MW and then increment by 500kW with 2 shots at each condition.
Apr 19 2006 10:24:03:817AM1060419006P. PhillipsInjection at 0.8s in middle of BT ramp.
Apr 19 2006 10:29:10:037AM1060419007P. PhillipsGood data during ramps.
Apr 19 2006 10:39:38:567AM1060419008P. PhillipsGood data during ramps. Next shot increase power to 1MW
Apr 19 2006 10:53:30:537AM1060419009P. PhillipsRF 1MW, good ramp data, do again.
Apr 19 2006 11:21:05:067AM1060419010P. PhillipsRF 1MW, good ramp data, next shot 1.5MW
Apr 19 2006 12:01:03:020PM1060419011P. PhillipsRF 1.5MW, good ramp data, repeat
Apr 19 2006 02:51:33:740PM1060419018P. PhillipsGood data in ramp, next shot 2MW RF
Apr 19 2006 03:03:36:100PM1060419019P. PhillipsDisruption at .6s no data during ramp.
Apr 19 2006 03:20:41:223PM1060419020P. PhillipsData OK, RF drop outs near ramp, 2MW
Apr 19 2006 03:30:11:960PM1060419021P. PhillipsDisruption 0.6s no data
Apr 19 2006 03:45:01:270PM1060419022P. Phillips2 MW, Good data during ramp, next shot 2.5MW
Apr 19 2006 03:57:31:600PM1060419023P. Phillips2.5Mw, Good data in ramp, one drop out at 1s in RF, repeat
Apr 19 2006 04:12:12:770PM1060419024P. Phillips2.5Mw, Good data in ramp, density drop in ramp down during RF, next shot 3MW.
Apr 19 2006 04:22:37:317PM1060419025P. Phillips3MW, drop outs during RF power, repeat
Apr 19 2006 04:33:59:317PM1060419026P. Phillips3MW, very good data in ramps, next shot try 3.5MW.
Apr 19 2006 04:49:48:287PM1060419027P. Phillips3.5Mw, drop outs in ramp down during RF, repeat
Apr 19 2006 05:01:17:207PM1060419028P. Phillips3.5MW, very good data in ramps, end of run.

Physics Operator Comments
Apr 19 2006 09:14:57:130AM1060419001Earl Marmarload from 1060414001
800 kA, 5.4 tesla, nl_04 target 1.0e20

plasma
startup looks a bit lumpy
early hards

Apr 19 2006 09:20:58:380AM1060419002Earl Marmarfine tune the nl_04 target (raise it a bit early); still looking for 1e20 in flattop

plasma
startup looks better
density got to about 1.1e20
neutral pressure much higher than on shot 1
Apr 19 2006 09:34:12:787AM1060419003Earl Marmarnl_04 target to 0.9e20
plasma
got nl_04 = 1.0e20 before the h-mode
Apr 19 2006 09:49:34:600AM1060419004Earl Marmarenable argon puff: 50 msec, starting at 0.3 s

plasma
nl_04 got to 0.9e20 before the h-mode
Apr 19 2006 10:10:21:363AM1060419005Earl Marmarsegment 2 Bt to -144400kA with ramp to -146700 in the middle of the shot
Ip to 600kA
nl_04 target to .8e20

plasma
Apr 19 2006 10:16:18:990AM1060419006Earl Marmarno pcs changes

plasma
Apr 19 2006 10:36:23:270AM1060419007Earl Marmarno pcs changes

plasma
Apr 19 2006 10:50:22:053AM1060419008Earl Marmarno pcs changes

plasma
some camac errors during store
no H/D, neutrons
Apr 19 2006 11:09:41:880AM1060419009Earl Marmarno pcs changes

plasma
disrupted during ramp-down
still having camac problems
Apr 19 2006 11:24:39:067AM1060419010Earl MarmarTF invert time to 1.6 seconds (from 2.8 s)

plasma
Apr 19 2006 12:27:48:583PM1060419011Earl Marmarno pcs changes

delay before the shot (camac problem fixed; TF thermocouple problem fixed)

plasma

some hards
Apr 19 2006 12:28:26:397PM1060419012Earl Marmarno pcs changes

power supply dud (no EF3)
Apr 19 2006 12:41:40:787PM1060419013Earl Marmaradd 2 msec to prefill puff (now 22 msec)
Apr 19 2006 01:45:20:100PM1060419013Earl Marmarno power test
Apr 19 2006 02:01:03:380PM1060419014Earl Marmarno power test
Apr 19 2006 02:12:05:897PM1060419015Earl Marmarno power test
Apr 19 2006 02:42:57:787PM1060419016Earl Marmarno power test
Apr 19 2006 02:43:32:630PM1060419017Earl Marmarplc EF3 only test
Apr 19 2006 02:52:00:427PM1060419018Earl Marmartry for plasma

prefill puff now 22 msec (up from 20 on shot 11)

plasma
Apr 19 2006 03:05:55:957PM1060419019Earl Marmarprefill puff back to 20 msec (from 22)

plasma
early disruption (0.60 seconds); injection?
Apr 19 2006 03:22:29:850PM1060419020Earl Marmarno pcs changes

plasma
early hards
Apr 19 2006 03:36:41:643PM1060419021Earl Marmarno pcs changes

plasma

another early disruption (0.6 s)
density is rising from 0.3 reaching 1e20 before the disruption
Apr 19 2006 03:44:56:083PM1060419022Earl Marmarlower nl_04 target to 7e19

plasma
Apr 19 2006 04:05:10:550PM1060419023Earl Marmarno pcs changes

plasma
Apr 19 2006 04:15:54:863PM1060419024Earl Marmarno pcs changes

plasma
Apr 19 2006 04:24:13:473PM1060419025Earl Marmarno pcs changes

plasma
Apr 19 2006 04:37:40:113PM1060419026Earl Marmarno pcs changes

plasma
early hards
steady h-mode, 3 MW RF
Apr 19 2006 04:49:09:037PM1060419027Earl Marmarno pcs changes

plasma
Apr 19 2006 05:02:28:700PM1060419028Earl Marmarno pcs changes

plasma

steady h-mode, 3.6 MW ICRF

Engineering Operator Comments
ShotTimeTypeStatusComment
109:02:31:067AMPlasmaOk
209:15:01:583AMPlasmaOk
309:27:30:240AMPlasmaOk
409:40:27:660AMPlasmaOk
509:59:01:363AMPlasmaOk
610:11:30:427AMPlasmaOk
710:23:56:753AMPlasmaOk
810:36:15:473AMPlasmaOk
910:49:47:910AMPlasmaOk
1011:15:11:787AMPlasmaOk
1111:57:41:147AMPlasmaOk
1212:17:12:740PMPlasmaBadEF3 ower Supply Flt
1301:39:38:490PMTestBadNo Camac Initiate Pulse
1401:51:29:927PMTestOkEF3 Test
1502:08:17:100PMTestOkEF3 Test
1602:26:56:630PMTestOkEF3 test
1702:36:54:003PMTestOkEF3 PLC Test
1802:47:26:160PMPlasmaOk
1902:59:58:067PMPlasmaOkPlasma Disruption followed by OH1 Self Power Circuit Firing
2003:14:44:427PMPlasmaOk
2103:27:11:660PMPlasmaOkPlasma Disruption follwed by a OH1 self powered overvoltage fault
2203:39:31:503PMPlasmaOk
2303:51:57:940PMPlasmaOk
2404:04:32:350PMPlasmaOk
2504:17:08:753PMPlasmaOk
2604:29:35:287PMPlasmaOk
2704:43:56:037PMPlasmaOk
2804:56:26:410PMPlasmaOk