Alcator C-Mod Run 930610 Information

Miniproposals

Miniproposal:

Date Filed:

Title:

First Author:

Session Leader: Yuichi Takase (shots 1-2)

Operators
Session leader(s):	Yuichi Takase
Physics operator(s):	Robert Granetz
Engineering operator(s):	Vinny Bertolino,Steve Fairfax

Engineering Operator Run Comment
continued plasma shots

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries

Session Leader Comments

Jun 10 1993 07:56:52:350AM Robert Granetz Session leader: Granetz
Assistant: Takase
Engineers: Bertolino/Fairfax

Start with shot 930609023 from yesterday. This one had a good sawtoothing
plasma for the first 0.110 s, then a minor disruption followed by MHD
oscillations. This initial disruption might have been due to the plasma
moving slightly upwards, or to the end of positive rate of current rise.

Commutation resistors:

OH1 0.0656 ohms
OH2U 0.0129
OH2L 0.0131
EF1U 0.1204
EF1L 0.1195

Ballast resistors:

EF2U 0.0454 ohms
EF2L 0.0460

Crowbar times were delayed to t=0.070 s starting with shot #016 yesterday.

Jun 10 1993 08:01:02:710AM Robert Granetz At about 07:00 the IGT read 4e-7 torr.

Jun 10 1993 09:48:13:550AM 930610001 Robert Granetz Fizzle. No current channel formed. Try it again.

Jun 10 1993 09:54:03:080AM 930610001 Robert Granetz Momentary power failure occurred between shots #001 and #002. Probably
will result in significant delay to restart power supplies, camac, lasers,
etc.

Jun 10 1993 10:39:50:960AM 930610001 Robert Granetz The fill pressure was at 6e-5 torr for this shot. The field null looked
very good, so for the next shot, lower fill pressure to 5e-5 torr.

Jun 10 1993 10:41:56:660AM 930610001 Robert Granetz The power glitch caused about a 1 hour delay, mostly because the alternator
had to come back to speed. It also shut down the interferometer laser, and
this can't be reset without access to the cell. We don't anticipate a
chance to do this until after the run is over.

Jun 10 1993 11:18:49:830AM 930610002 Yuichi Takase Shot 002 I_p to 60kA, then died.
Fill pressure 5.e-5.
Field null looks OK.
Several problems from the power glitch:
Piezo valve stayed open (TORVAC lost communication with the remote rack).
Air pressure was low (40psi).
TF bus Rog. not working right (integrator not reset).
TF shunt looks OK.
XTOMO data look crazy.

Will stop cooling, vent the cell, and fix whatever needs to be fixed.

Physics Operator Comments

Engineering Operator Comments

Shot Time Type Status Comment

1 09:29:13:110AM Plasma Ok small flash -- will repeat shot

2 10:41:19:030AM Plasma Ok 60ka plasma, torvac control problems

Session Leader Comments
Jun 10 1993 07:56:52:350AM		Robert Granetz	Session leader: Granetz Assistant: Takase Engineers: Bertolino/Fairfax Start with shot 930609023 from yesterday. This one had a good sawtoothing plasma for the first 0.110 s, then a minor disruption followed by MHD oscillations. This initial disruption might have been due to the plasma moving slightly upwards, or to the end of positive rate of current rise. Commutation resistors: OH1 0.0656 ohms OH2U 0.0129 OH2L 0.0131 EF1U 0.1204 EF1L 0.1195 Ballast resistors: EF2U 0.0454 ohms EF2L 0.0460 Crowbar times were delayed to t=0.070 s starting with shot #016 yesterday.
Jun 10 1993 08:01:02:710AM		Robert Granetz	At about 07:00 the IGT read 4e-7 torr.
Jun 10 1993 09:48:13:550AM	930610001	Robert Granetz	Fizzle. No current channel formed. Try it again.
Jun 10 1993 09:54:03:080AM	930610001	Robert Granetz	Momentary power failure occurred between shots #001 and #002. Probably will result in significant delay to restart power supplies, camac, lasers, etc.
Jun 10 1993 10:39:50:960AM	930610001	Robert Granetz	The fill pressure was at 6e-5 torr for this shot. The field null looked very good, so for the next shot, lower fill pressure to 5e-5 torr.
Jun 10 1993 10:41:56:660AM	930610001	Robert Granetz	The power glitch caused about a 1 hour delay, mostly because the alternator had to come back to speed. It also shut down the interferometer laser, and this can't be reset without access to the cell. We don't anticipate a chance to do this until after the run is over.
Jun 10 1993 11:18:49:830AM	930610002	Yuichi Takase	Shot 002 I_p to 60kA, then died. Fill pressure 5.e-5. Field null looks OK. Several problems from the power glitch: Piezo valve stayed open (TORVAC lost communication with the remote rack). Air pressure was low (40psi). TF bus Rog. not working right (integrator not reset). TF shunt looks OK. XTOMO data look crazy. Will stop cooling, vent the cell, and fix whatever needs to be fixed.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	09:29:13:110AM	Plasma	Ok	small flash -- will repeat shot
2	10:41:19:030AM	Plasma	Ok	60ka plasma, torvac control problems