Alcator C-Mod Run 930702 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Yuichi Takase (shots 1-25)

Operators
Session leader(s):Yuichi Takase
Physics operator(s):Joseph Snipes
Engineering operator(s): Unknown

Engineering Operator Run Comment
plasma run following overnight ecdc

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries

Session Leader Comments
Jul 2 1993 08:33:45:060AMJoseph SnipesRun Plan
Today's run is intended to test wall conditioning and gas fueling. The tokamak
was discharge cleaned until about midnight last night when the ECDC tripped out
then restarted just before 6:00 am until 8:00 am this morning. The RGA looks
reasonably good with only a small mass 28 peak. Base pressure is at 1 x 10**-6.
We will start with 930625025 changing the gas to B_SIDE_UPPER in H.

Jul 2 1993 09:28:01:880AM930702001Yuichi TakaseShot 001
Loaded from 930625025
added negative front porch on EF3 -50V from -14 to -1ms and
increased EF4 to 750A (was 665A).
Gas from B side upper (hydrogen), Pulse_gas 2
Fill gas hydrogen 3.5e-5
Discharge cleaned in He last night.

Good shot 330kA nel=4e19 late breakdown (9ms)

Jul 2 1993 09:40:10:420AM930702002Yuichi TakaseShot 002
300kA shark fin @ 0.2sec, disruptive after that.
Earlier breakdown (4ms), colder shot.

Jul 2 1993 09:55:12:320AM930702003Yuichi TakaseShot 003
Removed the second gas puff around .12s.

Starts out as a runaway shot, becomes thermal after 0.12sec.
Current drops, density jumps up, etc. (@ .12sec).

Jul 2 1993 10:15:13:680AM930702004Yuichi TakaseShot 004
Increased the initial gas puff.

Runaway shot.

60Hz on OH1 and OH2 are worse today compared to yesterday.

Jul 2 1993 10:40:22:650AM930702005Yuichi TakaseShot 005
Dropped EF4 to 700A (was 750A).
Fill pressure increased to 4.5e-5.

Good shot (thermal). 360kA

Jul 2 1993 11:14:13:670AM930702006Yuichi TakaseShot 006
Fill pressure decreased to 4.e-5.

DAQ2 didn't go.
No hybrid. No plasma.
Some of DAQ1 didn't go.

Jul 2 1993 11:30:57:190AM930702007Yuichi TakaseRepeat.
Good shot. 300kA nel=4.e19

Jul 2 1993 12:07:16:070PM930702008Yuichi TakaseShot 008
Increased gas puff around 50msec (a small change).
Added a gas puff pulse after the shot for Artur.

Disruptive shot. 250kA nel=4-5e19.

Jul 2 1993 12:03:03:290PM930702009Joseph SnipesShot 9
Fill pressure lowered from 4 to 3.7 x 10**-5 Torr. Late gas puff moved from
0.99 to 0.7 s to check pressure gauge. EF3 inverted front porch increased to
-75 V .

Jul 2 1993 12:19:46:120PM930702009Yuichi TakaseShot 009

Disruptive until about 0.16sec.
Limiter midplane density drops, limiter bottom density increases at this time.
Plasma density and soft X-ray also increase.

Jul 2 1993 12:31:17:080PM930702010Yuichi TakaseDecreased pulsed gas.

OK shot.
Plasma moves in after 0.21sec and down after 0.25sec.
Density drops after about .165sec.

Jul 2 1993 12:39:12:260PM930702011Yuichi TakaseShot 011
Decreased pulsed gas again.
Moved the late gas puff for Artur to 0.8sec.

Fizzled.

Jul 2 1993 12:51:04:900PM930702012Yuichi TakaseShot 012
EF3 inverted front porch changed back to -50V (was -75V).

Fizzled.

Jul 2 1993 01:16:55:450PM930702013Yuichi TakaseShot 013
Increased EF4 to 740A (was 700A).

Good shot. 340kA nel=3.5e19 @ .25sec.

Jul 2 1993 01:37:20:780PM930702014Yuichi TakaseShot 014
Moved EF3 inverted front porch turn on to -8msec (ramps from -9 to -7ms),

Good shot. 300kA nel=3.5e19.

Jul 2 1993 01:50:16:880PM930702015Joseph SnipesShot 15
Lowered EF4 current before breakdown to 725 A.

Jul 2 1993 02:03:15:690PM930702015Joseph SnipesShot 16
Lowered EF4 current before breakdown to 715 A. Increased prefill to 4 x 10**-5.

Jul 2 1993 02:03:48:570PM930702015Yuichi TakaseShot 015
Reduced EF4 to 725A (was 740A).
Added Ar puff (-100 to -90msec).

Lots of hards.

Jul 2 1993 02:16:02:870PM930702016Yuichi TakaseShot 016
Reduced EF4 to 715A.
Prefill 4.e-5.

Good shot. 340kA nel=4.e19.

Jul 2 1993 02:36:36:770PM930702017Yuichi TakaseShot 017
Ar puff increased to 80V (was 60V).
H puff moved earlier to -10ms (was -5ms).

Fizzled.

Jul 2 1993 02:54:07:240PM930702018Yuichi TakaseShot 018
Ripple on OH1 appears to be causing a problem on Bz.
Depending on which phase we hit, Bz can vary by about 15gauss.
Will go to 6 pulse instead of 12 pulse on OH1 for shot 018.

Runaway shot.

Jul 2 1993 03:09:51:040PM930702019Yuichi TakaseShot 019
The other 6 pulse on OH1.
Increased prefill to 4.5e-5.

OH1 cleaner. Didn't get EF3 inverted front porch.

Jul 2 1993 04:35:35:230PM930702019Yuichi TakasePrevious shot used the rear cabinet.
This shot used the front cabinet.
(The front cabinet is the good half.)

Jul 2 1993 03:20:30:920PM930702020Yuichi TakaseShot 020
EF4 reduced to 685A (was 715A).

Good shot. 340kA nel=3.2e19.

Jul 2 1993 03:34:39:050PM930702021Yuichi TakaseShot 021
Ar puff extended by 2ms (-100 to -88ms).
H puff start moved to -20ms.

Fizzled.

Jul 2 1993 03:44:00:990PM930702022Yuichi TakaseShot 022
H puff start moved to -5ms.

Good shot. 340kA nel=3.2e19.

Jul 2 1993 04:05:21:260PM930702023Yuichi TakaseShot 023
Ar puff increased to 14ms (-100 to -86ms).

Fizzled.
EF3 turned on by itself (500A) around -25msec.

Jul 2 1993 04:17:36:240PM930702024Yuichi TakaseShot 024
Ar puff increased to 14ms (-100 to -86ms).
Added 2nd Ar puff (.8 to .9sec) for Artur.

Fizzled again.

Jul 2 1993 04:32:57:250PM930702025Yuichi TakaseShot 025
Took out the negative front porch.

Fizzled.
Problem with EF3 again (-500A at -13ms).

Physics Operator Comments

Engineering Operator Comments
ShotTimeTypeStatusComment
108:56:56:540AMPlasmaOkno faults -- good plasma to start
209:26:59:040AMPlasmaOkno faults
309:42:13:020AMPlasmaOkno faults
410:04:27:680AMPlasmaOkno faults oh1 60hz worse than usual
510:22:59:040AMPlasmaOkno faults
610:53:17:020AMPlasmaBadhybrid problems
711:16:12:530AMPlasmaOkpower systems fired but problems with the data system
811:38:56:700AMPlasmaOkno faults
911:59:42:960AMPlasmaOkjd and fs
1012:16:00:890PMPlasmaOkok shot
1112:32:10:370PMPlasmaOkno faults
1212:44:18:150PMPlasmaOkno faults
1301:08:28:470PMPlasmaOkno faults
1401:28:20:200PMPlasmaOkno faults
1501:49:15:320PMPlasmaOkno faults
1602:05:42:240PMPlasmaOkno faults
1702:19:13:280PMPlasmaOkno faults
1802:42:09:340PMPlasmaOkno faults
1902:55:00:840PMPlasmaOkno fault
2003:11:08:180PMPlasmaOkno faults
2103:25:01:490PMPlasmaOkno faults
2203:36:30:640PMPlasmaOkno faults
2303:52:40:240PMPlasmaOkno fault
2404:09:24:150PMPlasmaOkno fault
2504:21:33:400PMPlasmaOkno faults