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
Jan 13, 2003
The Alcator
C-Mod maintenance period continued last week.
Work on
machine instrumentation, ICRF systems, Lower Hybrid MIE
Project, and
diagnostics progressed.
Operations
----------
We continued to work on upgrades to
the TF voltage tap, thermocouple, and
heater leads. We are approximately 70% done with this
project.
A conceptual design for a set of field correction coils has
been developed.
It is believed that non-axisymmetric error fields may have
affected plasma
performance during high current operation in the last
campaign. A set of
coils to be mounted on the igloo structure is proposed
to address this issue.
ICRF Systems
------------
The
placement of the current probes on the D and E Port antennas is
being
optimized using our rf simulation software.
These probes are
used to sense faults during operation. A problem with the motorized
13.8 kV
switch in the high yard has been identified and repairs are
progressing.
Lower
Hybrid MIE Project
------------------------
Work continued on
the new SFOL design. The Low Power
Microwave rack
SFOL receiver chassis assembly, including the wiring, is
complete.
The Low Power Microwave rack SFOL transmitter chassis assembly
is near
completion and the parts arrived to finish the I-Q detector
wiring
inside the chassis. Five
DFOLs for LH system controls have been
successfully tested. We continue to specify and procure cabling
for
the low power microwave rack and interconnections to the
launcher.
A temporary pump has been installed in the Lower Hybrid
water cooling
system while warranty work is being performed on the primary
pumps.
This pump will allow full power tests of the klystrons to be made
with
the HVPS.
MSE Diagnostic
--------------
Work
continues at PPPL and MIT on developing two approaches for
disruption-resilient
mirrors for the C-Mod Motional Start Effect (MSE)
diagnostic. An approach based on existing spare glass
(Vycor) mirrors
will use a stainless-steel rib structure that supports the
mirror
along its entire periphery, and 0.040" Teflon cushioning
between all
glass and metal surfaces.
The design of this approach is complete and
fabrication of test
components has started.
An alternate design is based on a metallic
substrate, Inconel
625, coated with silver and overcoated with a
dielectric for
protection against oxidation. A mechanical design has been completed
that reduces
disruption forces by removing most of the Inconel
substrate from the rear
of the mirror.
At the present time both designs are being carried
along in parallel.
Travel and Visits
-----------------
Monty
Grimes was at AFT in Germany last week reviewing progress on the
Lower
Hybrid MIE Project circulators.