From: IRBY@PSFC.MIT.EDU
Reply-To: IRBY@PSFC.MIT.EDU
Subject: Alcator C-Mod Weekly Highlights
Newsgroups: sci.physics.plasma
Organization: MIT


Alcator C-Mod Weekly Highlights
January 10, 2000



We continued focusing work last week on the DNB, RF, and invessel work
including the re-installation of the RF antennas. Work also progressed
on maintenance of C-Mod power systems.

Engineering:


All work was completed last week on the OH commutation switches. This work
primarily involved cleaning high voltage switches, checking high voltage
connections, improving some of the high voltage insulation, and generally
cleaning up in and around all the racks. General maintenance also continued
on the power supply breakers. Each breaker has been checked mechanically
according to the GE service procedures, hi-potted, and generally cleaned
up. Similar maintenance has also been completed on the TMX contactors.
All high current bus connections on the TMX supplies have also been
throughly checked out. Finally, another TMX supply is being brought on line
as a backup supply for the alternator exciter.

Invessel work included re-installation of the D and E antennas. The D-port
antenna will be declared installed as soon as the final torque check is
complete. Boron nitride tiles for the E-port antenna are being fit up invessel
after which they will have to be baked. A fitup of the J-port antenna outside
the vessel is nearly complete. Les Gereg and Joe Frangipani came up from
PPPL to direct this effort. Invessel installation of this antenna will begin
this week. Other invessel work included repair to the H-port flux loop
mentioned last week. Inner divertor modules have been removed from the
machine and are being machined to provide new views for inner wall
retro-reflectors. Work also continued on a new mirror mount to be installed
at A-Hor. This mirror will allow a much better TV view of the J-port antenna.

Work on the DNB included continued operation of the MOD/REG supply, and
commissioning of the engineering components of the CAMAC data acquisition
system. On Friday, the beam supplies were operated into the beamline for
the first time.


Physics:

Last Thursday a final design review of the new 2-D imaging bundle was held
via a video conference involving PPPL, MIT, and LANL. This new diagnostic
will view the edge plasma with sufficient temporal and spatial resolution
to study edge fluctuations. Reviewers from PPPL included Gerd
Schilling, Dan Simon, Larry Dudek, Bob Parcell, Steve Raftopolous, Dave
Johnson, and Stewart Zweben who was at MIT and is leading this effort.
Jim Terry, Earl Marmar, Jim Irby, Bob Childs, Rejean Boivin, and Brian
LaBombard from MIT, and Ricky Maqueda from LANL also participated.

A first meeting of a new density control group took place last week.
The purpose of the meeting was to open discussion on what techniques and
hardware will be needed to meet the density control requirements of AT
operation on C-Mod, particularly during long pulse operation with LH
current drive. Experiments to run during the next campaign that would
shed light on particle control issues were discussed, as were new wall
conditioning and pumping techniques.


Travel and Visits:

Stewart Zweben, Les Gereg, and Joe Frangiapani visited from PPPL last
week as mentioned earlier.

On January 4th Thomas Pedersen gave a talk at Risoe National Laboratory
in Denmark entitled "Impurity transport phenomena in the H-mode transport
barrier region in Alcator C-Mod."