Alcator C-Mod Run 1050302 Information

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Miniproposals
Miniproposal:355
Date Filed:11/12/2003
Title:ICRF Testing & Conditioning
First Author:Steve Wukitch
Session Leader:Steve Wukitch (shots 1-29)
Miniproposal:407
Date Filed: 1/19/2005
Title:Effects of 3D Error Fields on Magnetic Surfaces
First Author:Lang Lao
Session Leader:Lang Lao (shots 2-3)

Operators
Session leader(s):Steve Wukitch,Lang Lao
Physics operator(s):Earl Marmar
Engineering operator(s):Gary Dekow,Ed Fitzgerald

Engineering Operator Run Comment
MP#355: ICRF Testing and Conditioning

Session Leader Plans
Entered: Mar 1 2005 01:44:01:407PM
Author: Lang Lao
Piggyback MP#407 Error Field Effects on Magnetic Surfaces

PLAN: Apply A-coil with square wave 3 Hz modulation and G-top only 0.8 - 1.5 sec with various amplitudes and document effects on the separatrix location using Thomson plus ECE and other diagnostics if available.

A-Coil G-top only, 0.8 - 1.5 sec 3 Hz square wave modulation

Amplitudes: 1. 1.5 kA
2. 2.5 kA
3. 3.5 kA

If seeing interesting effects, will redo the shots but without RF.


Entered: Mar 2 2005 07:19:14:820AM
Author: Steve Wukitch
Plan:

We will continue the simple and dull plasma operation for antenna
conditioning . We want to obtain as many discharges as possible to
plasma condition D and E antennas and will be the focus of the run. J
antenna will be tested at 50 MHz using D(3He) minority. If, however,
D and E clean up quickly then we will lower the field to 3.5 T to use
D(H) minority. Start with vanilla LSN, 5.4 T, Ip=0.8 MA, nl_04=0.8
target discharge (1050218027). Upper null discharges can be run if
parties are interested (1050216013 is a good starting point). The aim
is to get 1 MW from each for 0.5 sec then combine and maximize
injected power. Monitor density and impurity evolution for trends
with RF power.
Entered: Mar 2 2005 11:40:55:927AM
Author: Lang Lao
MP 407

Move A-Coil modulation earlier 0.5 - 1.5 sec.

Use TS channel 8, GPC2 ECE channel 5-6 to monitor changes in edge magnetic surfaces.

Physics Operators Plans
Entered: Mar 1 2005 04:43:36:203PM
Author: Earl Marmar
MP#355: ICRF Testing and Conditioning
SL: Wukitch

Piggyback MP#407: Error Field Effects on Magnetic Surfaces
SL: Lang Lao

PO: Marmar

Overnight ECDC in D2, bake at 60C

Engineering setup:
Power systems as on 1050218027, except A-coil configuration is +G-top only

Gas setup:
-----------
fill B-Top with 6 psi D2 Hybrid Enabled (PG4)
fill B-side lower with 2 psi Ar Hybrid DISabled (PG1)
fill B-side upper with 15 psi He3 Hybrid enabled (PG2)
fill (former) C-side with 30 psi D2 Hybrid Enabled (PG3)

Torvac Setup:
--------------
GV1 closed, Bypass to RGA open
Torus gate valves closed for 5min after shot

Diagnostic gate valves: ECE (assuming no vac problems) open

Z-bolo/shutter open

Session Leader Summaries
Entered: Mar 2 2005 07:01:57:743PM
Author: Steve Wukitch
Summary:

E antenna conditioned to 1.9 MW in L-mode with voltages approaching 40
kV. At 5.4 T, we optimized the plasma to achieve H-mode discharges
and obtained short H-modes. J antenna was tested into plasma at 50
MHz and found to operate reasonably well in contrast to previous
efforts where FMIT#3 would not operate into plasma. The problem was a
transmitter instability that we have traced to the FPA and further
tests are required to precisely identify and understand its source.
In fact, reducing the frequency to 49.8 MHz, the instability was
restricted to 20-60 kW under vacuum loading. After fixing the RF
switch in D antenna line, we were unable to transmit significant power
to the antenna. We will begin troubleshooting the problem in vacuum
conditions tomorrow.

Physics Operator Summaries
Entered: Mar 2 2005 07:26:11:447PM
Author: Earl Marmar
The machine ran reasonably well, until the 1 MA disruption on shot 24. After that we got 4 fizzles in a row, and then only 1 plasma, on the last shot (29). Chasing the evolving wall conditions during the day, and especially after disruptions, continues to be a physop challenge.

ICRF got things done, including E-port up to almost 2MW into L-Mode, and J-port operated into plasma at 50 MHz, and showed some heating at 3.4 Tesla.

H/(H+D) was around 10% most of the day.

The piggyback MP was not run today: there were problems driving a single a-coil, which included overcurrent trip, and power supply oscillation. Observers in the cell saw evidence of coil-case arcing during the tests.

Shots 1-3 were a-coil tests.

Shot 4 was an EF3 test, required because of some maintenance that had been done on the supply.

On the last 2 plasma shots, (24 and 29), which disrupted shortly into rampdown, the a-side camera view (wide 1) shows significant heating of parts of the active mhd antennas; we need to keep our eyes on this.

Shot 19 was lost to a data system problem; first we lost updates, including for scopes and the logbook. Then Pat was silent during INIT. This resulted in a no-power cycle, and a short delay.

Scorecard:
plasmas 16
fizzles 8
tests 4
no power 1

total cycles 29


Session Leader Comments
Mar 2 2005 11:58:36:723AMLang LaoMP 407. Move A-coil modulation earlier 0.5-1.5 sec.
Mar 2 2005 12:04:14:320PMLang LaoUse TS channel 8, GPC2 ECE channel 5-6 to monitor changes in edge magnetic surfaces.
Mar 2 2005 12:24:02:757PMLang Lao1050302001 A-coil single G-top test shot had oscillations. Adjust A-coil power supply.
Mar 2 2005 12:19:03:223PM1050302001Steve Wukitch001 A-coil test
Mar 2 2005 12:38:33:880PM1050302002Lang LaoA-Coil test shot. Had sinusoidal oscillations on top of square wave. GPC2 ECE channels 5-6 had pickups from A-coil.
Mar 2 2005 01:11:42:147PM1050302004Steve Wukitch004 EF3 test
Mar 2 2005 01:40:28:573PM1050302005Steve Wukitch005 BT~5.4T, Ip~0.8 MA, nl06~0.8
D: 0.4 MW [0.6,1.5]sec
E: 0.8 MW [1.,1.5]sec
J: 0.4 MW [1.4,1.5] sec
result: plasma
D: max faults - bad match
E: ran 2 faults
J: j3 ran/j4 max faults
Mar 2 2005 02:12:44:197PM1050302006Steve Wukitch006 BT~5.4T, Ip~0.8 MA, nl06~0.8, 3He puff~100 msec@0.5 sec
D: 0.4 MW [0.6,1.5]sec
E: 0.8 MW [1.,1.5]sec
J: 0.4 MW [1.4,1.5] sec
result: plasma
D: max faults - bad match
E: ran
J: j3 ran/j4 max faults
Mar 2 2005 02:13:02:057PM1050302007Steve Wukitch007 BT~5.4T, Ip~0.8 MA, nl04~0.8, 3He puff~100 msec@0.5 sec
D: 0.4 MW [0.6,1.5]sec
E: 1.4 MW [1.,1.5]sec
J: 0.4 MW [1.4,1.5] sec
result: plasma
D: max faults good match
E: ran 7 faults
J: j3 ran/j4 max faults - bad match
Mar 2 2005 02:28:20:570PM1050302008Steve Wukitch008 BT~5.4T, Ip~0.8 MA, nl04~0.8, 3He puff~100 msec@0.5 sec
D: 0.4 MW [0.6,1.5]sec
E: 1.4 MW [1.,1.5]sec
J: 0.4 MW [1.4,1.5] sec
result: plasma
D: max faults good match
E: ran 2 faults
J: ran
next shot: overlap J
Mar 2 2005 02:28:49:230PM1050302009Steve Wukitch009 BT~5.4T, Ip~0.8 MA, nl04~0.8, 3He puff~100 msec@0.5 sec
D: 0.4 MW [0.6,1.5]sec
E: 1.6 MW [1.,1.5]sec
J: 0.4 MW [1.3,1.5] sec
result: NTP
Mar 2 2005 02:53:32:073PM1050302010Steve Wukitch010 BT~5.4T, Ip~0.8 MA, nl04~0.8, 3He puff~100 msec@0.5 sec
D: 0.4 MW [0.6,1.5]sec
E: 1.6 MW [1.,1.5]sec
J: 0.4 MW [1.3,1.5] sec
result: plasma
D: max faults good match
E: ran 3 faults
J: ran - CD phase (co- i think) phase setting is 150 deg
Mar 2 2005 03:37:01:120PM1050302011Steve Wukitch011 BT~5.4T, Ip~0.8 MA, nl04~0.8, 3He puff~100 msec@0.5 sec
D: 0.2 MW [0.6,1.5]sec
E: 1.6 MW [1.,1.5]sec
J: 0.4 MW [1.3,1.5] sec
result: plasma
D: max faults - still have problems
E: ran 2 faults
J: ran phase - 100 deg - [0,pi,pi,0]
Mar 2 2005 04:40:21:620PM1050302012Steve Wukitch012 BT~5.4T, Ip~0.8 MA, nl04~0.8, 3He puff~100 msec@0.5 sec
E: 1.6 MW [1.,1.5]sec
J: 0.4 MW [1.3,1.5] sec
result: plasma
E: ran 2 faults
J: ran phase - 100 deg - [0,pi,pi,0]
Mar 2 2005 03:44:38:323PM1050302013Steve Wukitch013 BT~5.4T, Ip~0.8 MA, nl04~0.8, 3He puff~100 msec@0.5 sec
E: 1.6 MW [1.,1.5]sec
J: 0.8 MW [1.3,1.5] sec
result: plasma
D: max faults - still have problems
E: ran 2 faults
J: ran 1 fault dig. phase - 100 deg - [0,pi,pi,0]
next shot: Bt~3.5T
Mar 2 2005 03:44:50:917PM1050302014Steve Wukitch014 BT~3.5T, nl04~0.8,
D: 0.2 MW [0.6,1.5]sec
E: 1.6 MW [1.,1.5]sec
J: 0.8 MW [1.3,1.5] sec
result: NTP
Mar 2 2005 04:08:04:120PM1050302015Steve Wukitch015 BT~3.5T, Ip~0.5 MA, nl04~0.5
E: 0.8 MW [1.2,1.5]sec
J: 0.8 MW [0.6,1.2] sec
result: plasma
E: ran
J: ran dig. phase - 100 deg - [0,pi,pi,0]
heating
Mar 2 2005 04:08:34:337PM1050302016Steve Wukitch016 BT~3.5T, Ip~0.5 MA, nl04~0.5
E: 0.8 MW [1.2,1.5]sec
J: 1.6 MW [0.6,1.2] sec
result: plasma
E: ran no heating
J: ran max faults dig. phase - 100 deg - [0,pi,pi,0]
Mar 2 2005 04:22:40:667PM1050302017Steve Wukitch017 BT~3.4T, Ip~0.7 MA, nl04~0.5
E: 0.8 MW [1.2,1.5]sec
J: 1.6 MW [0.6,1.2] sec
result: plasma
E: ran no heating
J: ran multiple faults at L->H transitions
dig. phase - 100 deg - [0,pi,pi,0]
Mar 2 2005 04:27:43:167PM1050302018Steve Wukitch018 BT~3.4T, Ip~0.7 MA, nl04~0.5
E: 0.8 MW [1.2,1.5]sec
J: 1.6 MW [0.6,1.2] sec
result: plasma
E: ran no heating
J: ran multiple faults
dig. phase - 100 deg - [0,pi,pi,0]
next shot: back to 5.4 T
Mar 2 2005 05:31:53:103PM1050302021Steve Wukitch021 BT~5.4T, Ip~1 MA, nl04~1
E: 1.5 MW [0.6,1.2]sec
J: 1.6 MW [1.2,1.5] sec
result: plasma - short H-modes
E: ran max faults
J: ran 8 faults
dig. phase - 100 deg - [0,pi,pi,0]
Mar 2 2005 05:32:06:587PM1050302022Steve Wukitch022 NTP
Mar 2 2005 05:58:20:540PM1050302023Steve Wukitch023 BT~5.4T, Ip~1 MA, nl04~1
E: 1.5 MW [0.6,1.2]sec
J: 1.6 MW [1.2,1.5] sec
result: plasma - short H-modes
E: ran 4 faults
J: ran 3 faults
dig. phase - 100 deg - [0,pi,pi,0]
Mar 2 2005 06:00:09:430PM1050302024Steve Wukitch024 BT~5.4T, Ip~1.2 MA, nl04~1
E: 1.5 MW [0.6,1.2]sec
J: 1.6 MW [1.2,1.5] sec
result: plasma - early disruption (locked mode)
E: ran max faults
J: ran max faults
Mar 2 2005 06:17:10:150PM1050302025Steve Wukitch025 NTP
Mar 2 2005 06:22:57:447PM1050302026Steve Wukitch026 NTP
Mar 2 2005 06:34:01:807PM1050302027Steve Wukitch027 NTP
Mar 2 2005 07:01:31:260PM1050302029Steve Wukitch029 BT~5.4T, Ip~1.2 MA, nl04~1.2
E: 1.5 MW [0.6,1.2]sec
J: 1.6 MW [1.2,1.5] sec
result: plasma
E: ran max faults
J: ran 5 faults

Physics Operator Comments
Mar 2 2005 12:23:49:350PM1050302001Earl MarmarFirst shot will be an a-coil only test, to check the ~3 hz modulation on G-top.

To be ready for subsequent plasma shots, load segment 1 from 1050301004, segment 2 from 1050218027,
then modify a-coil program to give nearly square modulation with 300 msec period, 25 msec ramps up to 4000
and down to 0.

Got faults on the a-coil power supply, and Byford reports at least one spark at
the coil case.
Mar 2 2005 12:44:24:617PM1050302002Earl Marmarreduce a-coil demand to 3000 A, from 4000 A. PLC voltage limit also reduced to 300 V from 600 V.
still showing sparks
Mar 2 2005 12:45:25:973PM1050302003Earl Marmarturn off modulation on a-coil
supply is oscillating and coil is still sparking
Mar 2 2005 01:03:13:287PM1050302004Earl MarmarEF3 only test
Mar 2 2005 01:25:56:527PM1050302005Earl Marmartry for plasma
there will be no a-coils today
plasma
H/(H+D) ~ 0.07
various flavors of ICRF
Mar 2 2005 01:44:32:103PM1050302006Earl Marmarreduce prefill puff by 2 msec (to 18 msec)
enable Argon puff
add 100 msec He3 puff, starting at 0.5 seconds

plasma
Mar 2 2005 02:03:27:370PM1050302007Earl Marmarno pcs changes

plasma
Mar 2 2005 02:20:20:073PM1050302008Earl Marmarreduce prefill puff by 1 msec (to 17 msec)

plasma
Mar 2 2005 02:27:40:980PM1050302009Earl Marmarno pcs changes

fizzle
Mar 2 2005 02:44:54:230PM1050302010Earl Marmarreduce prefill puff 1 msec (to 16 msec)

plasma
Mar 2 2005 02:58:25:290PM1050302011Earl Marmarno pcs changes

plasma
Mar 2 2005 02:58:48:587PM1050302012Earl Marmarreduce prefill puff 1 msec (to 15 msec)
Mar 2 2005 03:18:41:167PM1050302013Earl Marmarno pcs changes

plasma
Mar 2 2005 03:40:29:917PM1050302014Earl Marmarreduce prefill puff 1 msec (to 14 msec)

reduce I_TF to 94 kA (3.4 Tesla), ramping down in segment 2
reduce I_p target to 0.5 MA
reduce nl_04 target to 5e19

fizzle
Mar 2 2005 03:56:49:510PM1050302015Earl Marmarno further pcs changes relative to shot 14
NINJA is now puffing deuterium (shows up nicely on the A-side wide angle view)

plasma
Mar 2 2005 04:03:21:823PM1050302016Earl MarmarIp to 700 kA
nl_04 target to 8e19

plasma
disrupt in rampdown (400 kA)
Mar 2 2005 04:21:01:743PM1050302017Earl Marmarreduce prefill puff by 2 msec to 12 msec
reduce Itf to 91kA from 94kA

plasma
several short h-modes during j-port RF
Mar 2 2005 04:31:45:277PM1050302018Earl Marmarno pcs changes

plasma
hesitation during early current ramp
multiple short h-modes
Mar 2 2005 04:37:10:120PM1050302019Earl MarmarItf to -150kA
Ip to 1.00 MA
nl_04 to 1e20

no power shot; data system problem
Mar 2 2005 04:58:37:777PM1050302020Earl Marmartry again
no pcs chages
fizzle
late breakdown
Mar 2 2005 05:20:16:900PM1050302021Earl Marmaradd 3 msec to prefill puff, now 15 msec

plasma
multiple short h-modes, this time with E-port
Mar 2 2005 05:26:34:087PM1050302022Earl Marmarreduce prefill puff by 1 msec (now 14 msec)
fizzle
Mar 2 2005 05:32:33:963PM1050302023Earl Marmarno pcs changes
Mar 2 2005 07:11:17:307PM1050302024Earl Marmarreduce prefill puff by 1 msec (to 13 msec)
Ip to 1.2 MA
plasma
disrupt just after end of flattop
probable locked mode starting around 1.15 (sawteeth disappear)

active mhd antenna getting hot at the disruption; see wide1 video view from A-side
Mar 2 2005 06:11:08:323PM1050302025Earl Marmarreduce prefill puff by 2 msec to 11 msec
increase nl_04 target to 1.2e20

fizzle
Mar 2 2005 07:14:50:730PM1050302026Earl Marmarno pcs changes

fizzle
Mar 2 2005 06:38:47:743PM1050302027Earl Marmaradd 3 msec to prefill puff (now 14 msec)
fizzle
late breakdown
fill pressure has now gotten quite low
Mar 2 2005 07:00:16:120PM1050302028Earl Marmarraise prepuff 2 msec (to 16 msec)

EF4 10 amp more negative before t=0

fizzle
Mar 2 2005 07:11:20:243PM1050302029Earl Marmarno pcs changes

plasma

no obvious locked mode this time, but it disrupted a little later in rampdown
several power supplies are at limits near the end of flattop

6 points on each active mhd antenna are getting hot at the disruption;
visible on the wide1 video view from A-side

Engineering Operator Comments
ShotTimeTypeStatusComment
112:11:06:427PMTestBadC.Coil PS Type 1 Flt
212:26:34:943PMTestBadG-Top A-coil case arced
312:38:33:723PMTestBadG-Top A-coil case arced
401:05:58:100PMTestOkEF3 plc test
501:19:08:100PMPlasmaOk
601:37:26:230PMPlasmaOk
701:54:47:570PMPlasmaOk
802:10:30:980PMPlasmaOk
902:23:51:430PMPlasmaOk
1002:36:31:463PMPlasmaOk
1102:50:19:103PMPlasmaOk
1203:04:07:837PMPlasmaOk
1303:16:56:790PMPlasmaOk
1403:32:14:743PMPlasmaOk
1503:44:56:480PMPlasmaOk
1603:56:34:087PMPlasmaOk
1704:09:09:120PMPlasmaOk
1804:21:44:540PMPlasmaOk
1904:34:16:290PMTestBad
2004:52:18:430PMPlasmaOk
2105:11:16:650PMPlasmaOk
2205:24:34:697PMPlasmaOk
2305:37:06:087PMPlasmaOk
2405:51:55:260PMPlasmaOk
2506:05:10:260PMPlasmaOk
2606:18:56:197PMPlasmaOk
2706:31:18:620PMPlasmaOk
2806:43:41:760PMPlasmaOk
2906:56:13:730PMPlasmaOk