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


Alcator C-Mod Weekly Highlights
October 06, 2003


Preparations continued for plasma operation last week. Work continued
on lower hybrid and ICRF systems. Re-commissioning of the alternator
has begun.


New APS Fellow
--------------

The American Physical Society has elected Amanda Hubbard for
Fellowship in the Society, upon the recommendation of the Division of
Plasma Physics. This is a great honor, as election is limited to only
one half of one percent of the membership. It is a recognition by her
peers of her outstanding contributions to physics.

The citation on Amanda Hubbard's Fellowship Certificate will read:

"For significant contributions to the understanding of the plasma edge
pedestal formation and of the transition to an improved confinement
regime in magnetic fusion confinement devices."


Operations
----------

We continued checking out data, cooling, and power systems in
preparation for plasma operation. The new TMX supply and control
system which will provide approximately twice as much current for the
non-axisymmetric control coils is ready for power tests. The 120C
bake of the vessel was completed with very good results on Monday
while ECDC cleaning of the vessel walls continued throughout the week.
The machine has been cooled down to near operating levels to check
cryogenic control systems and to cooldown the machine structure.
Diagnostic systems including TCI, PCI, and Thomson Scattering, are
being aligned and brought back on-line, as is the data system.

On Thursday a high vibration level measured by one of the alternator
bearing sensors kept us from reaching full speed. After running at
lower speeds for several hours and after continued warm up, the
alternator was brought to full operating speed on Friday evening. The
vibration level on the bearing was still slightly higher than during
the last run campaign, but did not exceed the trip threshold. We are
consulting with GE to determine if any re-alignment might be required.


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

After consultation with Chris Brunkhorst, PPPL, FMIT#3 and #4 were
successfully tuned to 50 MHz last week. All ICRF systems should be
ready for plasma operation this week. Vacuum conditioning of the
antennas will begin today.


Lower Hybrid Systems
--------------------

Following the addition of baffles, acid pumps and heating elements to
the etching process last week, the ceramic bricks have now been
totally removed from two of the Lower Hybrid couplers, and about 20%
have been removed from the remaining two. Etching will continue over
the weekend.

Our brazing vendor has received eight 3-channel titanium prototypes
for further brazing tests. Doug Loesser, PPPL, traveled to the vendor
10/1-3 to deliver the prototypes and discuss the new tests. Previous
tests had suggested a strong preference for the brazing alloy Gapasil,
which is repelled by the ceramic rather than bonding to un-metallized
areas. Its wetting of the titanium is also controlled by Stop-Off, a
brazing mask, which should considerably reduce subsequent cleanup
time. The prototype brazes are now in progress.

All etching and the prototype brazes are expected to be completed by
10/8, and an inspection of the results and a final design review
preparatory to coupler rebrazing have been scheduled for 10/10 at
PPPL.

The alignment holes of both Forward Wave Guides have been reamed, and
pins have been installed, A successful trial fit of the end flanges
has been performed. Preparations for final assembly and welding are
under way and will be carried out following approval of the final
assembly procedure.


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

Matt Sampsell, UT-FRC, arrived on 10/3 to continue the preparations
for BES and CXRS operation during the coming campaign. Alan Lynn,
UT-FRC, will arrive on 10/4 to prepare the FRCECE diagnostic. Bill
Rowan, UT-FRC, completed the installation of optics and spectrometer
in preparation for the beam experiments that will begin with the
arrival next week of Marco Valisa, RFX. The new CXRS detector is now
operating under control of MDSPlus.

Manfred Bitter, Ken Hill, and Doug LaBrie, PPPL, were at MIT last week
re-installing the NSTX soft X-ray spectrometer with an improved
detector.

Amanda Hubbard and John Rice were in San Diega last week at the ITPA
meeting. Amanda attended the Pedestal sessions while John attended
the Transport and ITB sessions.

Professor Thomas Klinger, Max Planck Institute for Plasma Physics,
visited the PSFC and gave a seminar on W7AS results and plans for
W7-X. He also had discussions with the VTF group and with several
C-Mod physicists on the physics of HDH-mode on W7-AS compared with the
EDA H-mode on C-Mod.


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