Alcator C-Mod Run 1050726 Information

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Miniproposals
Miniproposal:370
Date Filed:11/15/2003
Title:Large Volume ITBs at 2.8 T with 50 Mhz ICRF
First Author:John Rice
Session Leader:John Rice (shots 1-37)

Operators
Session leader(s):John Rice
Physics operator(s):Earl Marmar
Engineering operator(s):Andy Pfeiffer

Engineering Operator Run Comment
MP307, Large Volume ITBs at 2.8T with 50 MHz ICRF, SL John Rice, PO Earl

Session Leader Plans
Entered: Jul 25 2005 03:04:21:667PM
Author: John Rice
MP307, Large Volume ITBs at 2.8T with 50 MHz ICRF

Start with an on-axis heating shot, such as 1040506023, at 0.5 MA, 3.4 T for RF tuning
and to establish H-mode.

Reduce B by 0.2 T shot to shot to arrive at 2.8 T, which should give an ITB,
such as seen in 1040506034. obtain good density and temperature profiles from
Thomson and Dalsa, as well as rotation profiles from HIREX.

Attempt central heating with second harmonic heating from the 80 MHz.

Argon (1 psi) and Ne (2 psi) should be mixed in the B-side lower plenunm, and enabled (40 ms).

Dalsa and Thomson necessary for this run.

Physics Operators Plans
Entered: Jul 25 2005 05:02:54:493PM
Author: Earl Marmar
Physop Plan 1050726
MP 370 Large volume ITBs, 2.8T, 50 MHz

SL: Rice
PO: Marmar

Overnight boronization
use 120 psi from 10%B_2D_6/90%He bottle
scan resonance from 50 to 103 cm, dwell at 52
normal fill pressures and duty factors

follow boronization with:
4 hours He ECDC (5e-5 torr gauge)
1 hour D2 ECDC (2e-4 torr gauge)

Engineering setup as on 1050725001

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 neon (mixed in plenum) Hybrid enabled (PG1)
leave B-side upper 15 psi He3, disabled (PG2)
fill B-main with 40 psi D2 Hybrid enabled (PG3)

Enable the following: NeSox, ECE and VUV gate valves, Z-bolo shutters

ICRF Setup: transmitters in run-on at 8:30

Load segment 1 from 1050725003
segment 2 from 1040506023 with appropriate updates

we may try the new A-coil feedback

start at 3.4 tesla with on-axis H-minority heating (50 MHz). Work down to 2.8 tesla to get off-axis ITBs, still H-minority (50 MHz). If getting good ITBs, add on axis heating with E-port (2'nd harmonic H, 80 MHz).

Session Leader Summaries
Entered: Jul 29 2005 01:45:46:550PM
Author: John Rice
Session Leader Run Summary for 1050726 MP370 Large Volume ITBs at 2.8 T w/ 50 MHz ICRF

This was a successful run that produced many ITB discharges, in particular at currents
of 0.45, 0.5, 0.6, 0.7 and 0.8 MA at 2.85T. The higher current ITBs had density peaking across
the entire plasma radius, indicating a foot location near the edge pedestal, the purpose
of the run. A few ITBs were obtained with low field side ICRF, and had narrower foot locations.
At the very end, there were a few H-modes produced with 2nd harmonic heating.
ITB shots of particular interest were 10, 18, 19, 22, 23, 24, 25, 26, 31 and 32.

Physics Operator Summaries
Entered: Jul 26 2005 05:27:12:293PM
Author: Earl Marmar
This was a very good run. The machine and RF ran well, with field, current and density scans of various flavors for the Mini-Proposal.

Startup was quite robust, with no particular post-boronization issues. The first shot fizzled; lowering the fill pressure seemed to solve the problem. Shot 21 was a dud; raising the fill worked for the next shot. Shot 34 had a late breakdown, got to 130 kA and then rolled over (big increases on z-meter and h-alpha around 20 msec); lowering the fill gave a dud; raising it gave 2 more plasmas at the end of the run.

Many of the startups had hesitations/bounces, with some hards.

40 msec argon/neon puffs were definitely causing problems with the plasmas. There was no argon/neon from shot 8 through the end of the run.

The last 2 shots had E-port only (80 MHz) at 2.7 tesla, with 2'nd harmonic hydrogen resonance near the axis. Both had EDA-like H-modes.

Many shots were run with q_95 at or below 3; they typically disrupted before the end of the programmed flat-top.

In piggy-back, Brock got the first stereo images of a lithium pellet, with 2 microsecond time resolution (shot 31). Striations are clearly visible in the images.

Scorecard:

1 fizzle
1 130 kA early death
2 duds
33 plasmas

37 data system cycles

Session Leader Comments
Jul 26 2005 09:21:56:213AM1050726001John Ricefiz
Jul 26 2005 09:22:21:090AM1050726002John Rice1.0 MA, 5.2 T fiducial
Jul 26 2005 09:38:44:247AM1050726003John Riceattempt at 3.4 T, 0.5 MA
disrupted
Jul 26 2005 09:53:37:557AM1050726004John Riceattempt at 3.4 T, 0.5 MA
disrupted
Jul 26 2005 10:05:52:260AM1050726005John Rice3.4 T, 0.6 MA
Jul 26 2005 10:21:47:590AM1050726006John Rice3.4 T, 0.6 MA
H-modes
Jul 26 2005 10:22:01:247AM1050726006John Rice3.2 T, 0.6 MA
H-modes
Jul 26 2005 10:32:57:370AM1050726007John Rice3.2 T, 0.55 MA
ELM-free H-modes
Jul 26 2005 10:47:08:510AM1050726008John Rice3.2 T, 0.55 MA
EDA H-mode
Ar off
Jul 26 2005 11:05:35:450AM1050726009John Rice3.0 T, 0.55 MA
EDA H-mode
ITB?

Jul 26 2005 11:17:04:747AM1050726010John Rice2.8 T, 0.55 MA
EDA H-mode
ITB

Jul 26 2005 11:31:12:340AM1050726011John Rice2.8 T, 0.5 MA
EDA H-mode
ITB

Jul 26 2005 11:39:20:667AM1050726012John Rice2.8 T, 0.5 MA
EDA H-modes
ITBs

Jul 26 2005 11:59:35:307AM1050726013John Rice2.65 T, 0.5 MA
EDA H-modes
ITBs

Jul 26 2005 12:07:40:400PM1050726014John Rice2.65 T, 0.5 MA
EDA H-mode
ITB
on-axis 2nd harmonic heating, 0.6 MW at 1.0 s
Jul 26 2005 12:22:47:620PM1050726015John Rice2.65 T, 0.5 MA
ELM-free H-modes
no ITB
no on-axis 2nd harmonic heating
Jul 26 2005 12:32:18:057PM1050726016John Rice2.65 T, 0.45 MA
EDA H-mode
ITB
on-axis 2nd harmonic heating
Jul 26 2005 12:51:03:700PM1050726016John Rice2.85 T, 0.45 MA
ELM-free H-mode
no ITB
on-axis 2nd harmonic heating
Jul 26 2005 12:54:59:307PM1050726017John Rice2.85 T, 0.45 MA
ELM-free H-mode
no ITB
on-axis 2nd harmonic heating
Jul 26 2005 12:57:57:620PM1050726018John Rice2.85 T, 0.45 MA
EDA H-mode
steady ITB
on-axis 2nd harmonic heating
Jul 26 2005 01:09:32:353PM1050726019John Rice2.85 T, 0.45 MA
EDA H-mode
ITB
no on-axis 2nd harmonic heating
Jul 26 2005 01:24:39:650PM1050726020John Rice2.85 T, 0.45 MA
EDA H-mode
ITB
on-axis 2nd harmonic heating
Jul 26 2005 01:32:42:293PM1050726021John Ricedud
Jul 26 2005 01:48:34:620PM1050726022John Rice0.6 MA, 2.82 T
EDA H-mode
ITB, held steady by
on axis 2nd harmonic heating
Jul 26 2005 02:00:07:667PM1050726023John Rice0.7 MA, 2.82 T
EDA H-mode
ITB, held steady by
on axis 2nd harmonic heating
beta N of 1.6
Jul 26 2005 02:27:57:900PM1050726025John Rice0.7 MA, 2.82 T
EDA H-mode
ITB
no on axis 2nd harmonic heating
beta N of 1.5
Jul 26 2005 02:40:27:853PM1050726026John Rice0.8 MA, 2.82 T
EDA H-mode
ITB?
on axis 2nd harmonic heating
beta N of 1.5
Jul 26 2005 02:56:09:963PM1050726027John Rice0.8 MA, 2.7 T
EDA H-mode
ITB?
on axis 2nd harmonic heating
beta N of 1.5
Jul 26 2005 03:06:36:480PM1050726027John Rice0.8 MA, 2.9 T
EDA H-mode
ITB?
on axis 2nd harmonic heating
beta N of 1.5
Jul 26 2005 03:06:44:450PM1050726028John Rice0.8 MA, 2.9 T
EDA H-mode
ITB?
on axis 2nd harmonic heating
beta N of 1.5
Jul 26 2005 03:19:47:853PM1050726029John Rice0.8 MA, 3.1 T
EDA H-mode
ITB?
no on axis 2nd harmonic heating
Jul 26 2005 03:32:21:090PM1050726030John Rice0.8 MA, 3.3 T
EDA H-mode
ITB?
no on axis 2nd harmonic heating
Jul 26 2005 03:47:24:510PM1050726031John Rice0.8 MA, 3.8 T
EDA H-mode
no ITB
no on axis 2nd harmonic heating
Jul 26 2005 03:53:15:510PM1050726031John Rice0.8 MA, 3.8 T
EDA H-mode
ITB
no on axis 2nd harmonic heating
Jul 26 2005 04:01:38:433PM1050726032John Rice0.8 MA, 3.9 T
EDA H-mode
ITB
no on axis 2nd harmonic heating
Jul 26 2005 04:13:58:760PM1050726033John Rice0.6 MA, 2.7 T
EDA H-mode
ITB
on axis 2nd harmonic heating
Jul 26 2005 04:22:40:900PM1050726034John Ricefiz
Jul 26 2005 04:23:21:417PM1050726034John Ricethat like died
Jul 26 2005 04:40:18:450PM1050726035John Ricedud
Jul 26 2005 04:51:41:400PM1050726036John Rice0.6 MA, 2.7 T
EDA H-mode with 2nd harmonic heating only
Jul 26 2005 05:03:46:120PM1050726037John Rice0.7 MA, 2.7 T
EDA H-mode with 2nd harmonic heating only

Physics Operator Comments
Jul 26 2005 09:11:37:933AMEarl MarmarOvernight boronization was accomplished. However, the magnetron had a problem, and there was only 1 hour ECDC in He, 1/2 hour in deuterium
Jul 26 2005 09:10:17:027AM1050726001Earl MarmarStart with a 5.2 tesla, 1 MA shot to evaluate boroniziation

load from 1050725010
reduce prepuff by 2 msec (to 20 msec)
PG2 (He-3) to 100 msec and enabled

fizzle; fields look ok
Jul 26 2005 09:33:54:700AM1050726002Earl Marmarreduce prefill puff by 3 msec to 17 msec

plasma
startup looks ok
short H-mode, then J-port faults
neutral pressure relatively high
Jul 26 2005 09:46:48:293AM1050726003Earl Marmarload segment 2 from 1040506023 (3.4 tesla, 500 kA)
recalc Ip predictor
remove clearin offset
turn off He-3 puff

plasma
disrupted near OH1 crossover
PF breaker pulled (after the disruption?)


Jul 26 2005 10:02:29:137AM1050726004Earl Marmarno pcs changes

similar disruption, slightly earlier
Jul 26 2005 10:10:35:323AM1050726005Earl Marmardelay and reduce a-coil
Ip to 600 kA
disable Argon/neon puff

plasma
nice steady H-mode, Prad decreasing with time
Prf 1.5 MW, all J
Jul 26 2005 10:31:08:200AM1050726006Earl Marmarincrease outer gap (reduce RCUR 2 mm)
decrease toroidal field to 3.2 tesla
enable argon/neon, 40 msec puff (had been 60 msec)

plasma
toggling between H and L mode
Jul 26 2005 10:41:40:997AM1050726007Earl Marmarlower Ip to 550 kA

plasma
similar H/L toggling

disrupt after lithium pellet (1.4 s)
Jul 26 2005 10:56:28:620AM1050726008Earl Marmardisable argon/neon puff

keep RF on until 1.5 seconds

plasma
nice steady H-mode; hints of peaking near the end of the RF pulse, and especially just after RF turnoff (1.5 seconds)
H89 ~ 1.7, H98y2 ~ .95
Jul 26 2005 11:11:33:760AM1050726009Earl Marmarreduce TF to 3.0 tesla
Ip to 500 kA

plasma
nice steady H-mode
small injection at 1.09 seconds (OH1 cross-over), takes a temporary bite out of the stored energy

ITB sitings on Thomson profiles
Jul 26 2005 11:21:51:793AM1050726010Earl MarmarTF to 2.8 tesla

plasma
steady H-mode
definite ITB density and impurity peaking
one RF trip, followed by increased rate of Prad rise
Jul 26 2005 11:27:51:103AM1050726011Earl Marmarno pcs changes
plasma
less steady, multiple RF trips, but still peaking
Jul 26 2005 11:50:27:340AM1050726012Earl Marmarno pcs changes

plasma
2 H-modes
less peaking
Jul 26 2005 04:33:47:293PM1050726013Earl MarmarTF to 2.6 tesla
plasma
Jul 26 2005 12:13:35:463PM1050726014Earl Marmarno pcs changes

try to add E-port in H-mode (second harmonic hydrogen on-axis)

plasma
got E-port, seemed to keep Te up in the center
still peaking through the H-mode
disrupt at 1.5 seconds
Jul 26 2005 12:26:34:933PM1050726015Earl Marmarno pcs changes

E-port off

plasma
2 H-modes, little or no peaking (ELM-freeish)


Jul 26 2005 12:37:23:887PM1050726016Earl MarmarIp to 450 kA

plasma
multiple H-modes; some peaking during the first H-mode
Jul 26 2005 12:49:19:183PM1050726017Earl MarmarTF to 2.8 tesla

plasma
H-modes, not steady
Jul 26 2005 01:00:07:213PM1050726018Earl Marmarraise target density, nl_04 to 6e19

plasma
steady H-mode
peaking, which appears arrested by E-port
Jul 26 2005 01:15:14:917PM1050726019Earl Marmarno pcs changes

plasma
no E-port
multiple H-modes
first H-mode peaks until back transition
Jul 26 2005 01:29:25:777PM1050726020Earl Marmarno pcs changes

E-port should be back on

plasma
first h-mode peaking; E-port does not appear to slow the peaking
Jul 26 2005 01:36:58:527PM1050726021Earl MarmarIp to 600 kA
target nl_04 to 8e19

dud
Jul 26 2005 04:32:29:700PM1050726022Earl Marmaradd 2 msec to prefill puff (now 19 msec)

plasma
steady h-mode
Jul 26 2005 02:08:28:027PM1050726023Earl MarmarIp to 700 kA
target nl_04 to 9.3e19

plasma
long H-mode, then J-port has a fault
disrupt at 1.38 s
Jul 26 2005 02:18:03:620PM1050726024Earl Marmarno pcs changes

plasma
steady H-mode
similar to 23; no J-port fault
disrupt 1.4 second (q_95 = 3, also losing the sawteeth)
Jul 26 2005 02:32:31:527PM1050726025Earl Marmarincrease A-coil demand by 500 amp

E-port off for this shot

plasma
long H-mode
disrupt at 1.33 seconds
Jul 26 2005 02:45:41:950PM1050726026Earl MarmarIp to 800 kA
target nl_04 to 1.06e20

plasma
H-mode
Beta_toroidal gets to 2%
disrupt at 1.37 s

Jul 26 2005 02:58:05:683PM1050726027Earl MarmarTF to 2.7 tesla

plasma
H-mode
q_95 = 2.55
disrupt at 1.29
Jul 26 2005 03:11:33:073PM1050726028Earl MarmarTF to 2.9 tesla

plasma
H-mode
disrupt at 1.41 s
Jul 26 2005 03:23:50:760PM1050726029Earl MarmarTF to 3.1 tesla
turn off E-port

plasma
H-mode
no obvious peaking
Li pellet kills it at 1.6 seconds
Jul 26 2005 03:37:31:353PM1050726030Earl MarmarTF 3.3 tesla

plasma
H-mode
disrupt after Li pellet at 1.6 s
Jul 26 2005 03:55:38:010PM1050726031Earl MarmarTF 3.8 tesla

plasma
nice steady H-mode, possible some peaking
disrupts after Li pellet (1.6 s)
Jul 26 2005 04:07:43:073PM1050726032Earl MarmarTF to 3.9 tesla

plasma
long H-mode
definitely peaking
Jul 26 2005 04:17:27:637PM1050726033Earl MarmarTF to 2.7 tesla
Ip to 0.6 MA
target nl_04 to 8e19

plasma
h-mode
Jul 26 2005 04:26:28:137PM1050726034Earl Marmarno pcs changes

late breakdown, made it to 130 kA and then died
Jul 26 2005 04:37:21:823PM1050726035Earl Marmarreduce prefill puff by 1 msec to 18 msec

dud
Jul 26 2005 04:57:08:620PM1050726036Earl Marmarincrease prefill puff by 2 msec to 20 msec

plasma
E-port only
2'nd harmonic hydrogen, H-mode
Jul 26 2005 05:11:08:370PM1050726037Earl MarmarIp to 700 kA
target nl_04 to 9.3e19

plasma
E-port only (2'nd harmonic H) H-mode
disrupt at 1.33 s; q_95 =2.9

Engineering Operator Comments
ShotTimeTypeStatusComment
109:04:27:830AMPlasmaOk
209:16:53:323AMPlasmaOk
309:33:24:137AMPlasmaBadself powered circuit oh1 opened PF breaker
409:50:36:340AMPlasmaOk
510:03:05:400AMPlasmaOk
610:18:46:997AMPlasmaOk
710:31:04:793AMPlasmaOk
810:43:34:527AMPlasmaOk
910:57:08:807AMPlasmaOk
1011:09:47:667AMPlasmaOk
1111:23:06:450AMPlasmaOk
1211:36:35:870AMPlasmaOk
1311:49:38:650AMPlasmaOk
1412:02:31:340PMPlasmaOk
1512:15:05:933PMPlasmaOk
1612:27:37:307PMTestOk
1712:40:12:213PMPlasmaOk
1812:52:45:807PMPlasmaOk
1901:05:01:887PMPlasmaOk
2001:17:34:463PMPlasmaOk
2101:30:11:293PMPlasmaOk
2201:42:43:557PMPlasmaOk
2301:55:10:917PMPlasmaOk
2402:07:47:027PMPlasmaOk
2502:20:23:823PMPlasmaOk
2602:33:04:167PMPlasmaOk
2702:45:45:900PMPlasmaOk
2803:02:22:103PMPlasmaOk
2903:14:51:277PMPlasmaOk
3003:27:50:103PMPlasmaOk
3103:43:30:277PMPlasmaOk
3203:56:02:870PMPlasmaOk
3304:08:33:027PMPlasmaOk
3404:21:03:510PMPlasmaOk
3504:33:45:557PMPlasmaOk
3604:46:25:370PMPlasmaOk
3704:59:32:650PMPlasmaOk