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
May 17,
2002
Effort focused this week on preparations for
pumpdown. Work also continued
on
ICRF, LH MIE Project, and RFX DNB systems.
Operations
----------
Invessel
work this week included final assembly of the ICRF antennas,
and
calibrations and checkout of many invessel diagnostics. Thermocouples
have been added to all the
antennas and will be read out with our new
fast TC scanner. The new thermocouples behind the inner
divertor are
operational and are already being read out through the
scanner. The
visible continuum
array, TV views, H_alpha, and CXRS diagnostics,
among others, were also
aligned and calibrated this week. First
pumpdown
is expected early next week.
The cryostat and bus
tunnel have been sealed and the GN2 purge
system was checked out and
debugged. It will go into full time
operation
early next week.
We
continue the migration of many of our analysis routines to the Linux
based
computers. EFIT is now fully
operational on the new machines.
Some routines, the TCI analysis for
example, are running 2.5 times faster
under Linux than on our fastest
Alphas.
The Hybrid Plasma Control Systems has been checked out and
is operational.
The magnet power systems are being brought back into
operation. Bus
Rowgoskis are being
calibrated, ground fault fuses and current monitors
checked and
calibrated, and bus voltage instrumentation checked. The
bus will have a final retorque at the end of next
week.
Lower Hybrid
MIE Project
------------------------
At PPPL, lab testing of
the Lower Hybrid launcher prototype is continuing.
The dielectric
constant of the ceramic window material has been
measured at 4.6 GHz, and
a thickness has been specified for final
fabrication. The window "bricks" are now on
order. Ethan Schartman, a
graduate
student at Princeton University, will be working on
LH modeling and code
development for his second year theory project.
He will develop a
parallel version of the LSC code to use in scenario
development for Lower
Hybrid AT experiments on C-Mod.
At MIT, the TPS Optical Interface
Board 2 has been completed. HVPS
commissioning
is progressing. The vendor estimates
they will be ready
for acceptance tests within the next two weeks.
ICRF
----
We
continue to work on the control and fault electronics. Calibrations
continue on the new phase
demodulator boards. Phase plots
indicating
output voltage vs input phase have been completed for all the
boards.
Cabling of the new racks is well underway. All invessel work on the
antennas was
completed this week including installation of the
new thermocouples, and
re-installation of the rf magnetic probes and
BN tiles.
RFX
DNB
-------
The DNB was operated briefly this week to test
operation following the
repositioning of some of the DNB equipment. The DNB duct and vacuum
interface to
the torus was completely assembled. The
optical bench for beam
spectroscopic monitoring was completed and
installed. The new fueling
system
is nearing completion.
The DNB was aligned relative to the tokamak
this week using an invessel
laser to illuminate the source grids.
Assembly of the CXRS
feedthroughs was completed. The shutter
controls were installed and tested, and the shutter position calibrated.
The CXRS toroidal channels were spatially calibrated. The CXRS
periscope at F-Top was
installed.
Alan Lynn, UT-FRC, provided in-vessel support for CXRS,
MSE, and BES
shutter assembly and for CXRS calibration. He also began assembly of
the
refurbished ECE high resolution radiometer.
He and Perry
Phillips, UT-FRC, will complete this next week. This was Alan's last
"visit"
prior to his taking up residence in Boston in June for the
duration of
the campaign. Ron Bravenec, UT-FRC,
collaborated with
C-Mod personnel on assembly of the BES/MSE optics and
continued BES
fiber polishing begun by Matt Sampsell a few weeks
back.
Travel and Visits
-----------------
Martha
Redi, PPPL, was at MIT May 13-17,
working with Catherine Fiore and
Paul Bonoli on gyrokinetic analysis of
off-axis RF heated plasmas,
which exhibit internal transport
barriers. Gerrit Kramer and Jay
Kung,
also PPPL, were at MIT May 15-17 to install the two new 130 and
140
GHz reflectometer channels for
fluctuation measurements farther up the
edge pedestal.