Alcator C-Mod Run 1060523 Information

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Miniproposals
Miniproposal:415
Date Filed: 2/24/2005
Title:Rotation and H-mode Power Threshold for LSN and USN at Different IP and ne
First Author:John Rice
Session Leader:John Rice (shots 1-14)

Operators
Session leader(s):John Rice
Physics operator(s):Bill Rowan
Engineering operator(s):Bill Cochran,Ed Fitzgerald

Engineering Operator Run Comment
MP#415 Rotation and thresholds

Session Leader Plans
Entered: May 23 2006 11:39:38:813AM
Author: John Rice
MP 415 calls for investigation of the H-mode power threshold in both USN and LSN with reversed
plasma current and toroidal field. This will be done first at 0.8 MA with nl04 = 1. This will
augment previous studies with normal field and current. The important diagnostics are ETS and
HIREX-Jr. The first item of business is to determine a suitable USN discharge without the X-point
in the ETS field of view. The ICRF power will then be ramped to get an estimate on the power
threshold, then the exact value will be determined shot-to-shot varying the steady power level.
The same procedure will then be used for a similar discharge with LSN, the 'unfavorable' drift
direction. If time permits, this will be repeated at 1.0 MA. Boronization between shots may
be required.

Physics Operators Plans
Entered: May 22 2006 02:44:04:617PM
Author: Bill Rowan
Engineering setup for Tuesday. 23 May 2006

MP#415 Rotation and thresholds

SL: Rice
PO: Rowan

Overnight ECDC in deuterium; bake at 60 C

The run will start at 09:00 and end at 17:00.

Power systems as on: 1060519016, USN

A-coil configuration: normal [-Dtop +Dbot +Jtop -Jbot] and enabled.

Gas Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar + 2 psi Ne Hybrid enabled (PG1)
leave B-side upper as is Hybrid DISABLED (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)
leave NINJA as is disabled

Enable the following gate valves and shutters, assuming no vacuum problems:
ECE, VUV, Z-bolo shutters


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ICRF setup: Transmitters #3 and #4 in run-on by 7:30, #1 and #2 in run-on by 8:30
(The ICRF group will vacuum-condition J-antenna before the run)
-------------------------------------------------------------------------------

Session Leader Summaries
Entered: May 23 2006 03:07:52:150PM
Author: John Rice
Session Leader Run Summary for 1060523 MP415 H-mode Power Threshold in USN and LSN with Reversed Current/Field

The run got to a late start (2 hour delay) due to a power supply problem, then was plagued at the begining
by a faulty pulsed gas valve (shots 1-6). Some shape development was performed (shots 7-13) for USN, to move
the X-point out of the ETS view. The H-mode power threshold was very near 1.0 MW of ICRF in an un-boronized
machine. Shot 14, the last of the day, was LSN with no H-mode at 2.3 MW. The run ended due to an alternator problem.

Physics Operator Summaries
Entered: May 23 2006 03:19:29:733PM
Author: Bill Rowan
The beginning of the run was delayed for two hours due to failure of a breaker in the TMX cabinets.

At the beginning of the run, piezo-electric gas valve PG3 failed to open to fuel the plasma. The valve was forced open by manually applying a voltage directly to it. This brought it back to life beginning with shot 007.

Shots 007 through 013 were USN. We started from shot 1060519016 and modified it to better agree with the (flipped) shape of the LSN discharge 1060519008.
Only one shot was obtained in LSN (1060519014) before an alternator fault ended the run.

Score card
plasmas 11 001, 002,003,007,008,009,010,011,012,013,014
gas tests 3 004,005,006
fizzles 0
duds 0
total 14

Session Leader Comments
May 23 2006 11:40:28:940AM1060523001John Riceno gas, but plenty of hard x-rays
May 23 2006 11:42:18:750AM1060523002John Riceno gas, but plenty of hard x-rays
May 23 2006 11:44:34:453AM1060523003John Ricedisrupted early, 0.31 s
May 23 2006 01:37:10:673PM1060523004John Ricetest
May 23 2006 01:37:19:673PM1060523005John Ricetest
May 23 2006 01:37:26:140PM1060523006John Ricetest
May 23 2006 01:37:44:487PM1060523007John Riceplasma, with ICRF ramp
May 23 2006 01:38:05:940PM1060523008John Ricestrange Ip and ne traces
May 23 2006 01:38:26:157PM1060523009John Ricegood plasma, ICRF ramp, strange H-mode
May 23 2006 01:48:27:797PM1060523010John Ricegood plasma, ICRF ramp, H-mode
May 23 2006 02:02:22:220PM1060523011John Ricegood plasma, ICRF ramp, H-mode near 1.0 MW
May 23 2006 02:14:08:220PM1060523012John Ricegood plasma, ICRF steady near 1.0 MW. H-mode?
May 23 2006 02:24:10:313PM1060523013John Ricegood plasma, ICRF steady near 1.3 MW. H-mode
May 23 2006 02:37:19:843PM1060523014John RiceLSN, good plasma, ICRF steady near 2.3 MW. no H-mode

Physics Operator Comments
May 23 2006 08:32:55:720AMBill Rowan
loaded 1060519016
0.8 MA, 5.5 T, nel_04=1e+20 m-2, USN

May 23 2006 08:33:48:407AMBill Rowan
Increase prefill from 16 ms to 18 ms
May 23 2006 08:48:00:563AMBill RowanDNB GV enabled for the first shot

May 23 2006 08:52:27:093AMBill Rowan
Delay of approx 1 hour (starting 8:50am). Replace a breaker in TMX cabinet.
May 23 2006 10:07:20:627AMBill Rowan
Delay continues: another hour (from 9:45am). Same problem.

May 23 2006 11:15:42:440AM1060523001Bill Rowan001. Power system test
May 23 2006 11:28:16:203AM1060523002Bill Rowan002. nl_04=2e_19 instead of the demand of nl_04=1e+20
May 23 2006 11:59:47:593AM1060523004Bill Rowan
004. gas test
added a pulse on pg3 of 100 ms at -1s

PG3 does not seem to be opening

May 23 2006 12:18:02:233PM1060523005Bill Rowan
005. gas test.
found a loose bnc connector after the previous shot and it was reinstalled

no improvement

May 23 2006 12:51:28:687PM1060523006Bill Rowan
006. gas test
prior to this test, the valve was opened using a manually applied ps pulse
worked

May 23 2006 01:04:16:343PM1060523007Bill Rowan007. plasma attempt
plasma. 1.7 s, disruption during rampdown
May 23 2006 01:16:49:500PM1060523008Bill Rowan008. RXU moved out by 1 cm
plasma

May 23 2006 01:33:07:297PM1060523009Bill Rowan
009. RXU moved out by 1 cm
plasma

May 23 2006 01:48:22:533PM1060523010Bill Rowan
010. increase outer gap to 1.0 cm Rcur reduced by 0.23 cm
outer gap is better

May 23 2006 02:02:21:780PM1060523011Bill Rowan
011.
lower ZXL by 1 cm
plasma

May 23 2006 02:11:54:423PM1060523012Bill Rowan
012.
lower zxl by 1 cm
plasma

May 23 2006 02:27:35:673PM1060523013Bill Rowan
013.
lower zxu by 2 mm


May 23 2006 02:37:31:610PM1060523014Bill Rowan

014.
The request was to load 1060519008.
Loaded seg 2 from that shot
turned off segment 3
turned on segment 2
LSN, 0.8 MA, 5.5 T, nl_04=1e20 m-2

May 23 2006 02:54:07:220PM1060523014Bill Rowan
end of the run.
alternator problem that will require more than two hours to diagnose

Engineering Operator Comments
ShotTimeTypeStatusComment
111:04:53:283AMPlasmaOk
211:20:28:610AMPlasmaOk
311:42:18:453AMPlasmaOk
411:54:59:690AMTestOkGas Test
512:11:24:640PMTestOkgas test
612:48:34:733PMTestOkGas test
701:01:24:813PMPlasmaOk
801:13:58:517PMPlasmaOk
901:27:53:673PMPlasmaOk
1001:42:36:440PMPlasmaOk
1101:55:22:000PMPlasmaOk
1202:08:13:390PMPlasmaOk
1302:20:45:987PMPlasmaOk
1402:33:26:423PMPlasmaOk