Alcator C-Mod Weekly Highlights
			    September 5, 2006


FY2006 weeks of research operations:
   JOULE target: 14 weeks
   Completed: 16.7 weeks


Operations
----------

Work continued in-vessel last week with removal of all of the upper
divertor protection hardware.  The new wedge plates that provide
primary support for the cryopump protection hardware were then
temporarily installed in the upper chamber so that fit-up data could
be collected.  The fit-up went well with the entire ring of fourteen
plates going into position easily.

Software needed to upgrade the PLC to PC interface for our magnet
supply control systems has been completed.  The computer hardware
needed to implement the new systems will be installed during the
current up-to-air period.

Routine maintenance continued on alternator systems last week.  Work
was completed on the gas heat exchanger system with only minor
refurbishment required.


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

Work continued last week on repairs to the lower hybrid high voltage
power supply. All required components have been ordered and should be
in-house soon.

The latest modeling results indicate that residual stresses on the
lower hybrid coupler windows can be reduced if a double flange
geometry is used with the windows located between the flanges.  This
result has application both to the current 24-window design and a
16-window design proposed for the 2nd lower hybrid launcher.


Cryopump
--------

The cryopump has successfully pumped hydrogen at approximately 13,000
Torr-l/s, which is consistent with estimates derived from pumping
speed measurements made in deuterium.  The ability to pump hydrogen
will be an important control knob for C-Mod since the hydrogen
background directly affects ICRF minority heating dynamics.


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

The FFT real-time matching system is working into static loads under
feedback control.  The control system has been able to quickly (~ 1
ms) bring an initially mismatched load into a matched condition as
seen by the transmitter.  Testing will continue with a dynamic load.

Work continued on removal of the ICRF antennas from in-vessel so that
a careful inspection of all hardware components can be made.


Visitors and Travel
-------------------

Vincent Tang visited General Atomics last Thursday and Friday to work
with Myunghee Choi and Vincent Chan.  They are comparing minority tail
results from Choi's ORBIT-RF simulations with the Vincent's CNPA
(Compact Neutral Particle Analyzer) data.

_______________________________________________
Cmod_weekly mailing list
Cmod_weekly@lists.psfc.mit.edu
http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly