Alcator C-Mod Run 1030529 Information

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Miniproposals
Miniproposal:318
Date Filed: 8/22/2002
Title:High Performance Operation at 5 Tesla
First Author:Earl Marmar
Session Leader:Earl Marmar (shots 1-27)

Operators
Session leader(s):Earl Marmar
Physics operator(s):Steve Wolfe
Engineering operator(s):Gary Dekow

Engineering Operator Run Comment
MP#318 - High performance H-modes at 5.3 T; SL: Marmar PO: Wolfe EO: Dek

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:32:803PM
Author: To Be Determined
Subject:
session leader run summary 1030529: High performance H-Modes at 5 Tesla
From:
"E. Marmar"
Date:
Mon, 02 Jun 2003 11:50:48 -0400
Newsgroups:
psfc.cmod.ops

This run was an attempt to satisfy one or both of

Milestone 67: Evaluate integrated H-mode performance with 6 MW ICRF, Ip \ge 1.2MA.

and the

FY03 plain english goal: Higher Performance Plasmas--
Produce high temperature plasmas with 5 Megawatts of radio frequency heating for pulse lengths of half a second. These plasmas should achieve conditions where the relative importance of plasma particle collisions is similar to what is expected for the burning plasma regime. The studies of the susceptibility of the plasma to instabilities and the losses of plasma across the confining field under these conditions should therefore be applicable to predicting the performance of next-step experiments.

The miniproposal for this run is MP 318, high performance H-Modes at 5.3 Tesla.

Results:

We made some progress toward the goals, achieving total ICRF powers ~5 MW for up to 0.1 s intervals on several shots. H/(H+D) fractions were typically in the 0.08 to 0.1 range, probably too high for optimal minority heating; radiated power fractions were also on the high side, and the H-modes were not steady state. The better shots include 7, 20, 22, 24, and 25, with operation at 1.2 and 1.0 MA.


Physics Operator Summaries
Entered: Jul 7 2004 04:37:18:020PM
Author: To Be Determined
Physop summary for Thursday, May 29, 2003

MP#318 "High performance H-modes at 5.3 T"
SL: Marmar
PO: wolfe

Setup and Plan
--------------
Overnight ECDC in D2 at 2e-4, bake at 60C

Power Systems as on 1030528030 (including C-coil)

Gas setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC)
fill C-side with 30 psi D2 Hybrid enabled (PG3)

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

Run Plan
--------

Start at 1.2MA, target density nl4~1e20, and wait for the RF guys to
get the power up to 4-5MW for 0.5sec. Raise the target density to 1.6e20 in 3
steps, and evaluate the EDA/ELM behavior. Choose best (by some definition)
target density and try to raise power to max available. Raise current to 1.4MA
and maybe the elongation and/or triangularity. Try for neutrons.

Results
-------

The main goals were to try to satisfy some combination of the PEG calling for
5MW of ICRF for 0.5sec and MP#67 for H-modes at 6MW, Ip>1.2MA. We were not
successful in either, although we did get closer than in previous attempts.
The confinement was not good; maximum Wmhd was around 170kJ at both 1.0 and
1.2 MA, even with launched power over 5MW.

We started at 1.2MA, with a slightly tweaked equilibrium derived from
1030528030. After a couple of unexplained disruptions, I reloaded seg2
from that shot, which seemed to eliminate the disruptions, although it
brought back a crossover thrash. We tried raising the density, and also
increasing the elongation and triangularity, getting q up to 3.6, but the
H-modes were not very eda-like. Between shot ecdc was used to restrain the
increase in H/D, which was rising during the shots from .07 -> .12. J-port had
difficulty staying on, and D had to be backed down in power to avoid
overshooting due to a feedback problem. Target density was increased to 1.3e20
(nl04).

At shot#16 we dropped the current to 1.05MA to try to increase the EDA
nature. This was moderately successful, but the radiation and H/D remained
high; Zeff and Mo were on the high side. It appears we need a fresh
boronization. The highest RF power obtained was 6.2MW for a very short
interval. We had several shots with RF over 5MW for multiple pulses over
100msec, but never got J to stay on for .5sec. E-port was the steadiest
performer, regularly running at 1.9MW for .6sec without faulting. Best shot
oveall may have been #25. Target density was dropped over several shots from
1.3e20 to 0.9e20 in an attempt to improve the RF situation. On shot#26 we
tried increasing the gaps, on the theory that this might reduce the loading
variability associated with gap changes at L-H and H-L transitions; this
seemed to make problems worse for the RF, so on shot#27 we tried decreasing
the gaps. This resulted in a disruption at 0.75sec.

On shot#26, BP13_JK, which is used in processed data (EFIT), died during the
shot. I replaced it in the processed set with BP13_BC, which is used in the
hybrid. The JK loop recovered on shot #27. The EFIT on shot#26 has been re-run
with the BP_12 weight turned off.


We ran the A-coil all day, in "suppression" phasing. There were no obvious
locked modes. ECDC between shots slows the cycle down by about 5minutes, but
seemed necessary given the H/D. After some tweaking I ended up with a PG4
pulse of 20msec, and we entered init fairly routinely at a base pressure of
3.5e-6Torr on ITG. Only one shot had significant runaways. Startups were
pretty reliable.

Scorecard
---------

Tests 0
Duds 0
Fizzles 2
Plasmas 25
------ --
Shots 27

Session Leader Comments
May 29 2003 09:32:23:263AMEarl MarmarToday's run is aimed at meeting the FY03 level 1 DOE milestone:

Higher Performance Plasmas [Sep 03]

Produce high temperature plasmas
with 5 Megawatts of radio frequency heating for pulse lengths of half
a second. These plasmas should achieve conditions where the relative
importance of plasma particle collisions is similar to what is
expected for the burning plasma regime. The studies of the
susceptibility of the plasma to instabilities and the losses of plasma
across the confining field under these conditions should therefore be
applicable to predicting the performance of next-step experiments.

May 29 2003 10:50:33:670AM1030529006Earl Marmarmultiple H-modes, looking pretty ELM-free

q_95 = 3.3

try increasing upper triangularity to increase q_95

H/(H+D) starts at 6%, rises to 10%

3.4 MW for first 150 ms, 150 kJ

Physics Operator Comments
May 29 2003 07:35:29:317AMSteve WolfeSetting up for High Performance Run (MP#318)

Plan:
Engineering Setup and Run Plan for Thurs. 5/29/2003

MP#318 "High performance H-modes at 5.3 T"
SL: Marmar
PO: wolfe

Overnight ECDC in D2 at 2e-4, bake at 60C

Power Systems as on 1030528030 (including C-coil)

Gas setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC)
fill C-side with 30 psi D2 Hybrid enabled (PG3)

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

Run Plan
--------

Start at 1.2MA, target density nl4~1e20, and wait for the RF guys to
get the power up to 4-5MW for 0.5sec. Raise the target density to 1.6e20 in 3
steps, and evaluate the EDA/ELM behavior. Choose best (by some definition)
target density and try to raise power to max available. Raise current to 1.4MA
and maybe the elongation and/or triangularity. Try for neutrons.

******************************************************************************
When I first brought up PCS this morning, I got the gui but no konsole window. Quit
and restarted it, and everything came up ok.

Load_from 1030528030 (last shot from yesterday)
Change seg2 title to indicate 1.2MA
Load/cleanLoad at 29-May-2003 07:34:14.00
Open tree /home/wolfe/pcs_scratch -1
Open tree done

May 29 2003 08:02:57:327AMSteve WolfeFor shot 1, tweak clearin to be a little larger before 0.4 to compensate
for the oh1 crossover lurch (from 0 to .005 at .428) and hold clearin constant
after 1.3 sec to keep from increasing n/ncrit in rampdown (which is at 1.3 sec
in this discharge).
Load at 29-May-2003 08:02:21.00
May 29 2003 09:08:52:663AM1030529001Steve Wolfeshot#1: plasma disrupted at 1.23 sec
tci dropped out in mid-shot.
got to 1.68kJ at .8 sec

No obvious reason for disruption; there's an injection just before,
but I can't see from where on the cameras.
May 29 2003 09:17:00:237AM1030529002Steve Wolfeshot#2: drop pg4 from 25->23 msec
fizzle. didn't drop it enough.

next shot: no change
May 29 2003 09:48:18:383AM1030529003Steve Wolfeshot#3: no change
disrupted at 0.56sec

next shot: load seg2 from 1030528030, drop pg4 to 20msec
May 29 2003 10:00:21:957AM1030529004Steve Wolfeshot#4: load seg2 from 1030528030, drop pg4 to 20msec
Got two factor prompts and two prompts for waveform name changed
on load. There is a timestamp problem in PCS

plasma full length. lots of H-modes
J has max faults, d&e ragged.

next shot: 5 minutes of ecdc between shots, no other changes.
May 29 2003 10:30:45:240AM1030529005Steve Wolfeshot#5: 5 minutes of ecdc between shots, no other changes.
init at 2.0e-6 on itg.

disrupted at .80sec, got to 150kJ
Can't see why it disrupts; e-port is on and sees the injection at .815,
but can't tell cause from effect.

next shot: reduce e-port power 20%.
May 29 2003 10:40:47:393AM1030529006Steve Wolfeshot#6: 5 minutes of ecdc between shots,reduce e-port power 20%.
init at 1.5e-6

plasma full length, 157kJ with 3.3MW, staying on a little better.

next shot: increase upper triang.
May 29 2003 11:01:27:970AM1030529007Steve Wolfeshot#7: 5 minutes of ecdc between shots; increase upper triang.
rxu in by 1cm; Argon down by 5msec (at JR's request)
init at 2.1e-6 on itg

plasma full length. multiple h-modes. 167kJ at about 3,4MW, staying on a little better.

next shot: increase triang and elongation more
May 29 2003 11:19:03:777AM1030529008Steve Wolfeshot#8: 5 minutes of ecdc between shots; increase triang and elongation more
zxu down by 1cm, rxu in by 1cm. init at 2.5e-6

plasma full length, lots of h-modes. 142kj

next shot: raise nl4 demand to 1.0e20
May 29 2003 11:45:07:393AM1030529009Steve Wolfeshot#9: 5 minutes of ecdc between shots; raise nl4 demand to 1.0e20
rxl from .011 to 0.000
init at 2.6e-6 on igt

plasma full length. multiple H-modes until 1.2sec
165 kJ in second h-mode.

next shot: raise zcur from -1.5 cm to -.9cm
May 29 2003 12:04:15:510PM1030529010Steve Wolfeshot#10: 5 minutes of ecdc between shots;raise zcur from -1.5 cm to -.9cm
init at 2.7e-6 on igt.
rf turns off power from d-port for this shot

plasma full length.

next shot: D will fire into dummy load.
May 29 2003 12:21:41:987PM1030529011Steve Wolfeshot#11: 5 minutes of ecdc between shots; D will fire into dummy load.
init at 3.0e-6

plasma full length, 3MW for awhile (E+J); 140kJ

next shot: D-port back in.
May 29 2003 12:48:46:413PM1030529012Steve Wolfeshot#12: 5 minutes of ecdc between shots; D into plasma again
init at 3.0e-6
plasma full length, lots of h-modes; a little over 155kJ
D-port is running away again.

RF guys found an open door. Maybe it's related

next shot: no changes
May 29 2003 01:08:20:907PM1030529013Steve Wolfeshot#13: 5 minutes of ecdc between shots; long delay for access. D into plasma again
init at 1.0e-6 on itg

plasma full length, bounced but survived.
170kJ, d is still running away and faulting.

next shot: raise nl4 demand to 1.2e20
May 29 2003 01:34:20:663PM1030529014Steve Wolfeshot#14: 5 minutes of ecdc between shots;
raise nl4 demand to 1.2e20; init at 3.4e-6

plasma full length. got to 155kj
still bouncing on startup

next shot: repeat
May 29 2003 01:44:48:517PM1030529015Steve Wolfeshot#15: 5 minutes of ecdc between shots; repeat
init at 3.5e-6
plasma full length, 5 hmodes
J isn't too happy, E is ok at 1.8MW, D steady at 0.5MW

next shot:drop current to 1.05MA
May 29 2003 01:59:38:933PM1030529016Steve Wolfeshot#16: 5 minutes of ecdc between shots;drop current to 1.05MA
init at 3.2e-6

plasma full length, 2 hmodes, more eda-ish, no J-port
d ran steady at 1MW, E at 1.9

next shot: repeat, hopefully with J
May 29 2003 02:12:30:507PM1030529017Steve Wolfeshot#17: repeat, hopefully with J. Still ecdc between shots.
init at <3.5e-6

fizzle, slow current rise.

next shot: no changes

May 29 2003 02:35:05:013PM1030529018Steve Wolfeshot#18: repeat, hopefully with J. no ecdc between shots this time.

plasma full length. 3 h-modes. 136kj, still not getting much out of J

next shot: repeat

May 29 2003 02:43:22:730PM1030529019Steve Wolfeshot#19: repeat, hopefully with J. ecdc between shots this time.
init at 3.5e-6

plasma full length. 2 h-modes, 135kj, still no luck on J

next shot: reduce nl4 to .9e20
May 29 2003 02:59:59:910PM1030529020Steve Wolfeshot#20: reduce nl4 to 0.9e20; ecdc, init at 3.5e-6
plasma full length, multiple h-modes.
target was 1.0e20
5,5MW for 90msec; got to 162kJ

next shot: repeat, try to keep J on better.
May 29 2003 03:20:40:497PM1030529021Steve Wolfeshot#21: repeat, try to keep J on better. ecdc, init at 3.5e-6
plasma full length, too many hmodes. 150kJ
got to 6.2MW for a very short time; d overshot again, J still having trouble staying on.

next shot: no changes ; try lowering J and D power a little.
May 29 2003 03:34:53:133PM1030529022Steve Wolfeshot#22: no changes ; try lowering J and D power a little.
ecdc, init at 3.2e-6
plasma full length; 170kj, 5MW for much of the pulse, but not steady.

next shot: drop the nl4 by 1e19
May 29 2003 03:52:02:720PM1030529023Steve Wolfeshot#23: drop the nl4 to 8e19
ecdc, init at 3.5e-6
plasma full length, lots of h-modes, 150kJ in second one.
J has two longer pulses, but 3 or 4 retries between them.

next shot: no change
May 29 2003 04:13:38:600PM1030529024Steve Wolfeshot#24: no change, long delay for a computer hang.
plasma, full length, too many h-modes

next shot: raise nl4 back up by 1e19
May 29 2003 04:33:19:280PM1030529025Steve Wolfeshot#25: raise nl4 back to 9e19
init at 3.5e-6 after ecdc

plasma full length, 4 h-modes. five ~100msec oulses from J
only 1 fault on d, none on e.

next shot: increase outer gap to try to minimize loading excursion in h-modes
May 29 2003 04:48:20:197PM1030529026Steve Wolfeshot#26: clearin from -.002 to +.002
init at 3.7e-6

plasma full length, 4hmodes
lost a loop. bp13jk has a baseline offset of 2.3
It went in the middle of the shot, so only efit is affected.

next shot: try decreasing the outer gap from previous.
May 29 2003 05:32:04:417PM1030529027Steve Wolfeshot 27: clearin to -.003

plasma disrupted early .75sec
not sure why, outer gap was at 3mm.

Engineering Operator Comments
ShotTimeTypeStatusComment
108:56:38:043AMPlasmaOk
209:13:56:130AMPlasmaOk
309:36:24:073AMPlasmaOk
409:55:44:130AMPlasmaOk
510:14:16:873AMPlasmaOk
610:34:27:303AMPlasmaOk
710:54:18:880AMPlasmaOk
811:13:36:513AMPlasmaOk
911:32:00:053AMPlasmaOk
1011:51:44:420AMPlasmaOk
1112:09:08:100PMPlasmaOk
1212:26:04:110PMPlasmaOk
1301:00:54:333PMPlasmaOk
1401:18:05:530PMPlasmaOk
1501:34:18:943PMPlasmaOk
1601:52:34:843PMPlasmaOk
1702:08:59:977PMPlasmaOk
1802:21:34:460PMPlasmaOk
1902:37:39:543PMPlasmaOk
2002:53:29:163PMPlasmaOk
2103:10:00:737PMPlasmaOk
2203:26:28:277PMPlasmaOk
2303:42:58:207PMPlasmaOk
2404:09:06:307PMPlasmaOk
2504:25:19:973PMPlasmaOk
2604:41:34:827PMPlasmaOk
2704:56:08:023PMPlasmaOk