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 18, 2002


Reassembly of Alcator C-Mod continued this week. Work also continued
on the ICRF systems, Lower Hybrid MIE project, and Inner Divertor Upgrade.


Physics
-------

The process of formalizing and scheduling the physics experiments
to be done during the next run campaign has been occurring over
the last two weeks. As a followup to the C-Mod Ideas Forum, the six
task-forces have prioritized the new ideas and the ideas still remaining
from the last campaigns. A meeting to discuss and set the overall allocation
of run-time among task-forces was held January 18th. Between now and the
start of the campaign, mini-proposals based on this review process
will be generated.


Operations
----------

Following successful torque checks on the OH2L coax, the cover plates
were installed, and the lower wedge plate raised. The upper wedge plate
was installed long enough to realign and fix the central column into
position. This alignment must be done to within 1 mm. Installation of
the lower TF arms will begin next week.

We have resumed work on the MOV protection system upgrade for the C-Mod
power supplies. This work was delayed somewhat to allow work to proceed
on more pressing tasks.

We continue work on the MHD antenna amplifiers, ratiomatic controller
boards, and TF and TC scanner electronics and software.


Lower Hybrid MIE Project
------------------------

We continue to work with representatives from the vendor to commission the
new HVPS. Safety interlocks for the supply have been tested, and an upgrade
to the power modules has been completed. We expect some high voltage testing
of the supply to begin next week with all output connections disabled.

A bearing problem with one of the new cooling water pumps required removing
the pump and sending it back to the vendor. It is expected back for
re-installation next week.


ICRF Systems
------------

The modelling of changes to the J-Port antenna straps has been completed
and plans are being developed for implementing the modifications. Machining
of the D and E-Port antenna Faraday shields continues.

A transmitter model including the drivers has been completed. We continue
to develop the plasma model to couple to this simulation.

Testing of the new phase demodulator continues with good results.


DNB and Related Diagnostics
---------------------------

The controls for the Budker beam were the focus of this week's work.
Signals between the PLC for the vacuum system and external equipment
were completely identified so that rewiring of the existing racks,
PLC and vacuum equipment can proceed.

The beam firing-cycle software and hardware for the Budker beam is
complete. This software runs on an alpha workstation and uses
MDSPlus as a database for beam pulse description. The TTL level
control pulses for the beam are generated in CAMAC. Using this
system, an operator can take conditioning shots while avoiding
collisions with C-Mod shots, synchronize the beam shots with C-Mod
shots, and activate any combination of DNB diagnostic data
acquisition for calibration or testing. At present, signals are
provided for gate valve control, and a single signal is provided for
beam firing. It is possible to modify the system to control
additional beam firing functions if a decision is made to replace the
Budker control system.

We are ready to start modifications to the support frame, energizing of the
AC power system, and machining of the F-port flange.

Work continued at PPPL on the MSE canister upgrades. Stainless steel parts
were sent to MIT to be black passivated by a local vendor. They will be
returned to PPPL for final assembly and testing. The optics canister has
been split at the vertical leg and flanges are being added by the PPPL
machine shop to allow easy assembly and view rotation. An excellent job of
glass cutting has been done by George Rose, a machinist in the Princeton
Geophysics department, in support of this project. PPPL will have the
upgrade ready for delivery to MIT by the first week in February.


Inner Divertor
--------------

All inner divertor tiles have been installed except the nose tiles. The
nose tiles will be installed as soon as the inner wall tile cassettes are
back in place. Proper sequencing of this installation is required so that
the chevron keys that lock the wall tile hardware to the inner divertor
hardware can be accomplished. We will do multiple torque checks on all
these components, after which the divertor tile keeper hardware can be tack
welded into position.


Travel and Visits
-----------------

A workshop of the National Fusion Collaboratory project took place last week
at the PSFC. Visitors included David Schissel from GA, Doug McCune from PPPL,
Kate Keahey from ANL, and Mary Thompson from LBNL. Detailed discussions took
place on merging the functionality of the Akenti and Globus grid computing
systems with the MDSplus data system to provide the fusion community with
secure access to fusion data and computing resources. Martin Greenwald, Josh
Stillerman, Stuart Sherman and Tom Fredian from the PSFC participated in the
workshop.

Stefano Bernabei and Remi Dumont from PPPL were at MIT on 1/16 to discuss
the LH physics scenarios with Amanda Hubbard, Paul Bonoli, and Ron
Paker. Gerd Schilling, PPPL, was at MIT 1/17-1/18 for programmatic
discussions and to participate in the C-Mod campaign planning meeting.
This meeting was also attended via videoconference at PPPL by
Stefano Bernabei, Remi Dumont, Gerrit Kramer, David Mikkelsen, Raffi
Nazikian, and Stew Zweben. Bill Rowan and Perry Phillips participated
from the University of Texas.