Alcator C-Mod Run 1020801 Information

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Miniproposals
Miniproposal:312
Date Filed: 6/14/2002
Title:Ohmic H - modes
First Author: Lee
Session Leader: Lee (shots 1-28)

Operators
Session leader(s): Lee
Physics operator(s):Earl Marmar
Engineering operator(s): Unknown

Engineering Operator Run Comment
MP312: Rotation profiles in Ohmic H-mode; SL: Davis Lee; PO: Marmar; EO:

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:29:630PM
Author: To Be Determined
Mini-Proposal #312

Goal of MP #312:
The prupose of this experiment is to investigate the shape of the rotation
profile for Ohmic H-modes. There are two reasons for this experiment. First,
for use as a comparison to ICRF H-modes. Second, to determine the shape of
the profile with an eye on the transport mechanism. This investigation would
be part of a larger set of data pertaining to Ohmic H-mode, ICRF H-mode, and
plasma rotation.



We are trying to get highly repeatable Ohmic H-Modes. We have made rotation measurements. We will use these data as background for future ICRF H-mode and ITB discharges.

We started by loading 990521014

Shot 001 --
Disruption at about about 1.46 s
No H-Mode, no rotation measurements

Shot 002 --
Disruption at about about 0.31 sec
No Ar puff, no rotation measurements.

Shot 003 --
Fizzle

Shot 004 --
No rotation information
no H-Mode

Shot 005 --
no rotation data
no h-mode
Right Gap os better

Shot 006 --
no rotation data
no h-mode

Shot 007 --
Core rotation measured, other signals improving.
no h-mode

Shot 008 --
Fizzle

Shot 009 --
rotation measurement (Although bad ones) on all tangential spectrometers
no H-Mode, only marginally satisfactory.

Shot 010 --
Rotation measurements are good, while there was plasma
No H - mode

Shot 011 --
Rotation measurements are good, while there was plasma
No H - mode, short shot 1.0 sec, but fairly decent while it lasted.

Shot 012 --
No rotation measurements
No H - mode, short 0.7xx sec

Shot 013 --
No rotation measurements, to speak of
No H - mode, short 0.7 sec disruption

Shot 014 --
Fizzle

Shot 015 --
H- mode, good rotation measurements
disruption is this shot's only drawback
Oh boy, was that great!

Shot 016 --
No Rotation data, low count rate
no H mode, disruption 0.68

Shot 017 --
Disruption 0.26 s
didn't make it to the Ar puff

Shot 018 --
H-Mode!
rotation measurements are great, while there is plasma
short shot though

Shot 019 --
H-Mode!
rotation measurements are fairly good, while there is plasma

Shot 020 --
Fizzle

Shot 021 --
H-mode
All rotation signals look fairly good, signals on
F and K spectrometers cut out around 1.0 sec

Shot 022 --
Fizzle

Shot 023 --
Low count rates, no rotation data
No H-mode

Shot 024 --
Low count rates, no rotation data
No H-mode

Shot 025 --
H-Mode
Rotation measurements, all measurements look good while
there is plasma.

Shot 026 --
H-Mode
Rotation measurements, best thus far today.
All have decent signal, all have rotation

Shot 027 --
disruption 0.61
no H-Mode, no rotation data

Shot 028 --
H-mode
Good rotation measurements
All have decent signal, all have rotation

Physics Operator Summaries
Entered: Jul 7 2004 04:37:15:520PM
Author: To Be Determined
#36 of 38 OPS
Date: 1-AUG-2002 17:52 Expires: 15-AUG-2002 00:00
From: VUV::MARMAR
Subj: Physop run summary 1020801

Physop run summary -- 1020801

Run Plan and Engineering Setup for Thursday, August 1, 2002

MP312: Rotation profiles in Ohmic H-mode

SL: Davis Lee
PO: Marmar


Run to begin at 9:00 AM
ECDC from 06:00-07:00 at 2e-4 Torr D2.

Power systems setup the same as for Shot 1020731002
Gas setup:

B-Top 6 psi D2 Hybrid Enabled (PG4)
B-side lower 1 psi Ar Hybrid Enabled (PG1)
B-side upper 10 psi D2 Hybrid DISABLED (PG2, for ECDC)
C-Side 30 psi D2 Hybrid Enabled (PG3)
J-Bottom leave as is, Hybrid DISABLED

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

RF Setup: ICRF will not be running into plasma today

Run Plan: set up a shot similar to 990521014, and then run it repeatedly for
Davis to get good statistics on the rotation profiles (using HIREX). The DNB
and LPI plan to piggyback, with a goal of coordinating the MSE and lithium
pellet cigar measurements to compare field angle profiles from the two
techniques.

Summary: We had significant difficulty getting ohmic H-modes, but once we found
it, it was fairly reproducible. The change that got us into H-mode was to lower
the toroidal field more than was done on the original target shot, to about 3.6
Tesla at 1.05 MA. There were many shots that disrupted early; causes included
impurity injections of unknown origin, ejecta from J-port, and mhd activity that
may have been associated with q_95~2.7. Shots with H-modes for the miniproposal
were 15, 18, 19, 21, 25, 26, and 28. The DNB and LPI were piggybacking, and we
got lithium cigar and MSE data nearly simultaneously on shot 21.

Scorecard:

23 Plasmas
5 Fizzles
________
28 total shot cycles

Session Leader Comments
Aug 1 2002 11:38:34:957AM1020801001 Disruption at about about 1.46 s
No H-Mode, no rotation measurements
Aug 1 2002 11:40:34:053AM1020801002 Disruption at about about 0.31 sec

No Ar puff, no rotation measurements.
Aug 1 2002 11:41:08:087AM1020801003 Fizzle
Aug 1 2002 11:50:05:483AM1020801004 No rotation information
no H-Mode
Aug 1 2002 11:54:22:477AM1020801005 no rotation data
no h-mode
Right Gap os better
Aug 1 2002 11:55:05:027AM1020801006 no rotation data
no h-mode

Aug 1 2002 11:56:00:370AM1020801007 Core rotation measured, other signals improving.
no h-mode

Aug 1 2002 11:56:12:013AM1020801008 Fizzle
Aug 1 2002 12:14:21:507PM1020801009 rotation measuremant (Although bad ones) on all tangential spectrometers
no H-Mode, only marginally satisfactory.
Aug 1 2002 12:26:46:427PM1020801010 Rotation measurements are good, while there was plasma
No H - mode
Aug 1 2002 12:48:01:977PM1020801011 Rotation measurements are good, while there was plasma
No H - mode, short shot 1.0 sec, but fairly decent while it lasted.
Aug 1 2002 12:48:54:120PM1020801012 No rotation measurements
No H - mode, short 0.7xx sec
Aug 1 2002 01:13:02:313PM1020801013 No rotation measurements, to speak of
No H - mode, short 0.7 sec disruption
Aug 1 2002 01:13:18:393PM1020801014 Fizzle
Aug 1 2002 02:19:55:373PM1020801015 H- mode, good rotation measurements
disruption is this shot's only drawback
Oh boy, was that great!
Aug 1 2002 02:22:02:990PM1020801016 No Rotation data, low count rate
no H mode, disruption 0.68

Aug 1 2002 02:23:01:193PM1020801017 Disruption 0.26 s
didn't make it to the Ar puff
Aug 1 2002 02:42:29:660PM1020801018 H-Mode!
rotation measurements are great, while there is plasma
short shot though
Aug 1 2002 03:00:09:857PM1020801019 H-Mode!
rotation measurements are fairly good, while there is plasma
Aug 1 2002 03:02:27:190PM1020801020 Fizzle
Aug 1 2002 03:37:19:773PM1020801021 H-mode
All rotation signals look fairly good, signals on
F and K spectrometers cut out around 1.0 sec
Aug 1 2002 03:37:35:210PM1020801022 Fizzle
Aug 1 2002 03:43:49:503PM1020801023 Low count rates, no rotation data
No H-mode
Aug 1 2002 04:07:21:560PM1020801024 Low count rates, no rotation data
No H-mode
Aug 1 2002 04:20:00:900PM1020801025 H-Mode
Rotation measurements, all measurements look good while
there is plasma.
Aug 1 2002 04:42:38:187PM1020801026 H-Mode
Rotation measurements, best thus far today.
All have decent signal, all have rotation
Aug 1 2002 04:53:04:307PM1020801027 disruption 0.61
no H-Mode, no rotation data
Aug 1 2002 05:16:04:203PM1020801028 H-mode
Good rotation measurements
All have decent signal, all have rotation

Physics Operator Comments
Aug 1 2002 09:02:21:930AMEarl Marmarcoldstart; no errors; all matrices respond
Aug 1 2002 09:04:19:400AMEarl Marmarloaded

segment 1 from 1020731011
segment 2 from 990521014; recalculated predictors
Aug 1 2002 09:30:15:687AM1020801001Earl Marmarplasma; density feedback was bad (interferometer problem)

no H-mode
Aug 1 2002 09:46:21:807AM1020801002Earl Marmartweak TF ramp to come back to 5.3 tesla for MSE

plasma; early disrupt (possibly vertically unstable + too much gas)
Aug 1 2002 10:10:04:003AM1020801003Earl Marmarfizzle
Aug 1 2002 10:06:52:103AM1020801004Earl Marmarload segment 1 from 1020731007; raise BR_offset to 0.0025 from 0.002

load segment 3 from 1020731011; turn off segment 2, turn on segment 3;

increase I_p request to 1.1 MA

plasma; disrupt at 0.8 s
Aug 1 2002 10:35:42:687AM1020801005Earl Marmardecrease RCUR .002 m (to increase outer gap by 4 mm)

plasma

disrupted slightly earlier
Aug 1 2002 11:01:52:170AM1020801006Earl Marmarreduce nl_04 demand to 0.9e20; reduce I_p flattop request to 1.0 MA from 1.1 MA

plasma; disrupt at 1.3 s (post-pellet); feedback failed, gas full on for most of the shot
Aug 1 2002 11:21:22:040AM1020801007Earl MarmarReduce minimum TF during mid-shot to 110kA from 120kA

Go to preprogram for PG3

plasma; very low density (programmed for 3%; should have been 30)

disrupt promplty after lithium pellet

Still no H-mode
Aug 1 2002 11:49:07:810AM1020801008Earl MarmarIncrease preprogram PG3 waveform

fizzle
Aug 1 2002 11:59:41:253AM1020801009Jim IrbyAdded 1 ms to the prefill gas just to have done something.
Fizzle on shot 008 probably related to the disruption on shot 007.
Aug 1 2002 05:44:40:520PM1020801009Earl Marmarplasma

no H-mode
Aug 1 2002 12:41:27:680PM1020801010Earl Marmarincrease time at minimum TF by 0.1 s

increase I_p to 1.05 MA from 1.0

Plasma

disrupt at 0.94 s
Aug 1 2002 12:43:00:840PM1020801011Earl Marmarkeep TF low after it ramps down

Plasma

disrupt at 0.99 s
Aug 1 2002 12:57:15:370PM1020801012Earl MarmarI_p to 1.15MA

turn nl_04 feedback on

plasma

disrupt 0.73 s

Aug 1 2002 01:17:53:543PM1020801013Earl Marmarreduce RXL by .02

reduce nl_04 request to 7e19

plasma

disrupt 0.71

Aug 1 2002 01:19:12:970PM1020801014Earl Marmarreduce B_t at bottom of ramp to 3.4 T

fizzle

Aug 1 2002 01:29:11:197PM1020801015Earl MarmarI_p to 1.1 MA

plasma

2 ELM-free H-modes

Disrupt at 0.93 s

Aug 1 2002 01:45:10:590PM1020801016Earl MarmarRaise ZCUR by 1 cm

plasma

disrupt at 0.68 s

Aug 1 2002 01:58:13:840PM1020801017Earl Marmarreload 1020801015

lower I_P to 1.05 MA

plasma; disrupt at 0.25 s (early injections)

Aug 1 2002 03:04:36:807PM1020801018Earl MarmarI_p to 1.0 MA

Plasma; disrupt at 0.87;

1 H-mode

Aug 1 2002 02:35:37:770PM1020801019Earl MarmarBring TF back up starting at 0.7 s

plasma

2 H-modes

got LPI at 1.25 & then prompt disruption

Aug 1 2002 03:01:56:613PM1020801020Earl Marmarno pcs changes

fizzle

Aug 1 2002 03:31:11:210PM1020801021Earl Marmarno PCS changes

plasma

1 H-Mode

LPI ends it at 1.26

Aug 1 2002 03:31:29:710PM1020801022Earl Marmarno PCS changes

fizzle

Aug 1 2002 03:49:53:270PM1020801023Earl MarmarB_R offset to .0020 from .0025

Delay TF ramps by 100 msec (Try to get H-mode later)

plasma

disrupt at 0.74

Aug 1 2002 05:43:55:267PM1020801024Earl Marmarplasma

no H-mode

disrupt at 0.74 s
Aug 1 2002 04:18:21:833PM1020801025Earl Marmarreload segment 3 from shot 21

reduce I_p after 1.0 s

plasma; 1 H-Mode; disrupt at 0.825 s

Aug 1 2002 04:45:15:520PM1020801026Earl Marmarno PCS changes

plasma; 2 H-modes; nice rampdown

Aug 1 2002 04:46:49:917PM1020801027Earl Marmarno PCS change

plasma; disrupt at 0.62; big injection at .55; no H-mode

Aug 1 2002 05:10:43:987PM1020801028Earl Marmarno PCS change

plasma

1 H-mode

disrupt at 1.11 s

Engineering Operator Comments
ShotTimeTypeStatusComment
109:04:24:930AMPlasmaOk
209:27:59:360AMPlasmaOk
309:44:35:790AMPlasmaOk
410:02:58:360AMPlasmaOk
510:19:43:040AMPlasmaOk
610:42:55:233AMPlasmaOk
711:04:04:300AMPlasmaOk
811:21:21:777AMPlasmaOk
911:37:39:173AMPlasmaOk
1012:14:06:227PMPlasmaOk
1112:30:22:717PMPlasmaOk
1212:43:25:057PMPlasmaOk
1312:56:38:307PMPlasmaOk
1401:10:24:400PMPlasmaOk
1501:24:00:967PMPlasmaOk
1601:42:13:710PMPlasmaOk
1701:55:36:570PMPlasmaOk
1802:08:52:270PMPlasmaOk
1902:23:59:510PMPlasmaOk
2002:58:25:900PMPlasmaOk
2103:11:08:150PMPlasmaOk
2203:24:03:367PMPlasmaOk
2303:39:21:667PMPlasmaOk
2403:52:22:523PMPlasmaOk
2504:11:09:007PMPlasmaOk
2604:29:23:110PMPlasmaOk
2704:42:21:763PMPlasmaOk
2804:56:43:910PMPlasmaOk