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
April
26, 2002
Assembly of Alcator C-Mod continued with the
installation of upper cooling
lines, coax connections, curved bus, and
port extensions. We continued
work
on ICRF and Lower Hybrid systems, and invessel installations. An FFOC meeting
was held at MIT on
4/24.
Physics
_______
Paul Bonoli and Eduardo
D'Azevedo of the Computer Science and
Mathematics Division at ORNL
completed a series of numerical
simulations of mode converted ion
Bernstein waves in the Alcator C-Mod
tokamak. In this work the number of
poloidal modes used in a spectral
representation of the ICRF electric
field was increased from 161 to 255
and then to 511 modes. In the 511 mode
simulation, the spectral
coefficients used to reconstruct the electric
field were found to be
converged on every flux surface in the plasma.
These simulations were
done by D'Azevedo on a single Power4 Node of the
IBM SP at ORNL using
31 threads. The 511 mode simulation required 11.5
CPU hours. Work is
now on-going at MIT and ORNL on a fully parallelized
version of the
matrix solver used in these simulations. The work will be done
by
D'Azevedo, John Wright, and Paul Bonoli as part of the RF Sci-Dac
initiative.
Operations
----------
On
Wednesday, a meeting of the FFOC (Fusion Facilities Operations
Committee)
was held at MIT to discuss issues related to 21 weeks of
operation for
DIIID, NSTX, and Alcator C-Mod during our FY2003 campaigns.
Availability
of personnel, spare components, safety issues, and general
operational
plans and scheduling were discussed.
Peter Perterson attended
from GA.
Al Von Halle, Gary Oliaro, and Mike Williams came from PPPL.
Catherine
Fiore, Martin Greenwald, Ian Hutchinson, Jim Irby, Earl Marmar,
Miklos
Porkolab, Josh Stillerman, David Terry and Steve Wolfe represented
MIT. Warren Marton and Esther Ku attended from
DoE.
Assembly of C-Mod this week involved installation of the curved
bus that
feeds current to the coils from the bus tunnel, installation of
upper TF
cooling lines and cooling panels, and installation of several
more
horizontal ports (7 of 10 now installed). The scheduling for installation
of the remaining horizontal
ports is now determined by the progress of other
installations that must
be completed before the ports can be installed.
TORVAC, the Alcator C-Mod
pumping station, has been installed on the
H-Hor flange and will be wired
up and tested over the next few days.
We continue to bring the C-Mod
computer cluster back online as well as the
various data acquisition
highways. The CAMAC engineering highway
is now
ready for operation.
The diesel generators that provide
emergency backup power for C-Mod systems
in the event of a power failure
have been brought into operation and
tested. All the equipment required to auto start the generators and
properly
switch them online has also been tested.
ICRF
Systems
------------
The 1200 C bake of the BN tiles has been
completed and the oven is now
being cooled down. We expect the tiles back on-site by early next week.
Cleanup
and polishing of the D and E port antenna boxes is complete and
the
Faraday shields are invessel ready for installation. Installation of
the LH cooling lines displaced the ICRF coax
that ran along the east wall
of the cell.
Re-installation of the coax along a somewhat higher path is
now in
progress.
We continued testing of the new boards needed for the
diagnostic, control,
and fault systems.
Fabrication of rack hardware also continued.
Lower
Hybrid MIE Project
------------------------
A Status Review
meeting of the C-Mod Lower Hybrid launcher project was
held at PPPL on
4/25. Ron Parker and Miklos Porkolab
came from MIT;
Stefano Bernabei, Joel Hosea, Doug Loesser, Gerd
Schilling, Skip
Schoen, and Randy Wilson attended from PPPL.
The
following components are now at PPPL:
Couplers, coupler flanges,
shroud assembly, interface flange, rear
mating flange, bellows flanges,
transition box, Helicoflex vacuum seals,
port extension, ceramic brick
test pieces, and ball screws. These were shown to the meeting
attendees.
The following LH components are expected to be delivered
to PPPL in the
coming weeks: High
strength bolts (4/26), prototype gaskets (5/24), support
members (5/30),
forward stacked waveguide (6/1), ceramic windows metallized
(6/5), and
vacuum bellows (6/15).
The following LH procurement packages are in
preparation at PPPL: Rear
stacked
waveguide, high power phase shifters, dummy loads, and WR-187 elbows,
tees
and straight sections.
The following LH activities are in progress
at PPPL: Fit-up and design
modification
on delivered sub-assemblies, prototype validation, ceramic
brick
dielectric constant measurements at 4.6 GHz, RF gasket design, and
prototypes
for the final coupler braze.
At MIT, the high-pressure water cooling
system has been checked out with
full flow through all of the 12
available klystrons. A flow rate of
at
least 60 gpm was achieved in each klystron at a differential
pressure
of 73 psi.
RFX DNB
-------
The
water cooling and gas systems for the DNB made progress this
week. The water cooling system hardware has been
completed. Proper flow
rates have
been measured through the DNB and these rates will soon be
recorded via
PLC. Components are being fabricated
for the gas system.
Quotes are being requested for the new LN2 feedline
for the DNB and
invessel cryopump.
Diagnostics
-----------
The
MSE optical can has been successfully fitup invessel and we are now
preparing
for alignment and calibration. The edge
CXRS telescope has also
been successfully fitup invessel along with its
shutter.
Travel and Visits
-----------------
Paul
Bonoli attended the 2002 International Sherwood Theory Conference
in
Rochester, NY, from April 22-24, 2002. He gave a poster presentation
entitled
"Fully Converged Solutions of Mode Converted Ion Bernstein
Waves in
Toroidal Geometry".
Ron Bravenec, UTexas, arrived at C-Mod
Monday and has helped with the
MSE/BES periscope installation and
subsequent optical system modifications.
He also installed an overhead
rack in the DNB diagnostics area for
the CXRS and BES fiber
corrloks.
Miklos Porkolab and Ron Parker attended the Furth Memorial
Event at the
Princeton Plasma Physics Laboratory on Thursday, April
25. On the same
morning, they
participated in an internal review of the Lower Hybrid launcher
design for
C-Mod. They also had a tour of the fabrication laboratory and
participated
in detailed discussions regarding fabrication processes and
procedures.
Good progress was noted in regard to the launcher fabrication
process.