Alcator C-Mod Weekly Highlights
                 August 23, 2004


FY 2004 weeks of operation planned: 18 weeks, completed: 18.9 weeks.

We are currently up-to-air with the primary goal of installing the
lower hybrid launcher.  In addition, a large number of in-vessel
activities are ongoing in support of ICRF and diagnostic systems.
Maintenance and upgrades to diagnostic and power systems are also in
progress.


Physics
-------

Summer student Istvan Cziegler from Eotvos Lorand University in
Hungary has begun analysis of data from the "ultra-fast"
Gas-Puff-Imaging camera that shows the first observation of the
Quasi-Coherent mode (QCM) by that diagnostic. The 250kHz/300 frame
camera has better spatial resolution (1-2 mm) than any of the other
optical diagnostics that see the QCM and is non-perturbative. Thus it
has the potential of resolving the radial width of the QC
mode. Preliminary result shows the mode width to be ~5 mm. In
principle, the camera can determine the mode wave-number as well. This
wave-number analysis is forthcoming.

Jessica Baumgaertel, a Summer Undergraduate Laboratory Intern at PPPL,
working with Martha Redi, has submitted a manuscript to appear as a
PPPL report entitled "Marginal Stability of Microturbulence near ITB
Onset on Alcator C-Mod".


Operations
----------

We continued cleanup and repair work on the first wall moly tiles.
Assembly of the EF1 conic heat shield and ceiling modules is well
underway.  Some modules have been completed and vacuum baked in
preparation for installation.  Fabrication of replacement outer
divertor tiles has been completed in our shop.

The software upgrade for the PC to PLC interface for the LN2 magnet
cooling system is now operational and undergoing testing.  Maintenance
of the magnet cooling system also proceeded with inspection and
cleaning of several LN2 filters.


Power Systems
-------------

Work continued on preventative maintenance and inspections of several
MIT alternator systems.


Lower Hybrid System
-------------------

A PPPL coupler was copper plated last week and is being prepared for
brazing this week.

A technique to reduce crazing in the outer-most edges of the
outer-most coupler windows is being tested. Plates of alumina are
brazed on the outside of a 3-window sample to counteract residual
stresses developed during brazing in the neighboring window.  Results
will be available early in the coming week.

Testing is complete, and we are ready to install the new klystron
filament control boards on a klystron cart for testing.  We have also
finished the transmitter cart #3 solenoid power supply upgrade.  All
four power supplies were tested for remote operation.  Remote analog
output instrumentation was also calibrated.  Installation of of the
remaining supplies on carts #1 and #2 is proceeding.


ICRF System
-----------

We are setting up the fast ferrite tuner in the power room where high
power testing of this system can be done.  Plans for installation of
the electrical and cooling utilities are being made.

We continued work on the rf simulation of the new 4-strap antenna
design.

Maintenance and inspection of transmitter control systems continued.


Diagnostics
-----------

Calibration of the MSE system using magnetic fields generated by
several hundred amps of current applied to the EF4U magnet continued
last week.  The results are now refined enough to confirm that the
discrepancy between in-vessel calibration data and beam-into-gas
calibration data is not caused by Faraday rotation in the MSE optics.

The new CO2 laser for the two-color-interferometer is operational
and will undergo frequency stability tests over the next few weeks.


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