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
March 21, 2003
Following
invessel cleanup and documentation Alcator C-Mod has been
pumped
down. Work continued on machine
instrumentation and hardware,
and ICRF and Lower Hybrid MIE systems.
Operations
----------
After
invessel cleanup and documentation Alcator C-Mod was pumped down
on Monday
evening. Heater systems, and cryo and
thermocouple
instrumentation were brought on-line in preparation for LN2
cooldown
of the magnets. The
installation of the new LN2 sump is progressing
and should be ready for
operation next week.
We continued to bring up data system components.
Neutron
calibrations were carried out successfully on Thursday, and on
Saturday
and Sunday Thomson scattering systems were calibrated using
a hydrogen
backfill.
ICRF Systems
------------
The J-Port
antenna, transmission lines, and tuners have been
successfully modeled
using Agilent ADS (EESOF). The code
output matches
closely network analyzer results, indicating the model can
be used to design
components for operation at 53 MHz. Work is continuing on estimates
of the
cost and schedule for the fast matching ferrite tuner project.
The
coupling from the J-Port ICRF antenna to the Active MHD antennas
between G
and H ports has been measured at all ICRF frequencies of
interest. The
coupling was found to be acceptable (better than -23db)
Lower
Hybrid MIE Project
------------------------
Work at MIT has
continued on the operator control program for the
timing system, which we
expect to start testing next week. Work
on
the timing system hardware design details and schematic has been
completed,
and lay out of the printed circuit board has begun.
Initial assembly
of the forward waveguide, bellows, enclosure box, and
port extension was
completed at PPPL successfully this week.
All
components mate well and are aligned. The coupling between the
launcher bearings and the port
extension rail yielded a higher than
expected coefficient of
friction. This bearing and rail system
allows
the launcher to be positioned radially relative to the plasma. The
rail material is being changed from
300 series stainless steel to
Stellite 6BH, a much better bearing
material. After replacement with
the
Stellite, testing of radial motion under vacuum can begin along
with
further leak checking of the launcher assembly. The rf losses of
both rear waveguide sections have been measured
to be lower than
expected, and the split ratio of the 3 dB splitter is 3.0
+/-0.1 dB.
The standard component loops and the high power phase shifters
have
also tested satisfactorily.
Work is proceeding to determine the
required phase length shims which
must be added to each loop prior to
installing them onto the rear stacked
waveguide. The shims will be
machined
at PPPL. Two of the four couplers have
now been copper
plated successfully.
The remaining two are now being plated.
The
rear faces of the couplers will then be trimmed for correct
metal
gasket compression when fit to the forward waveguide.
Trips
and Visits
----------------
Dennis Whyte, UCSD, visited this
Tuesday and Wednesday, and gave a
PSFC seminar on disruption mitigation
with high pressure gas puffs.
He worked with several collaborators
including Bob Granetz on
disruption mitigation, and radial transport
analysis and the
development of a surface analysis diagnostic with Bruce
Lipschultz.
Martin Greenwald traveled to Washington D.C. for a
meeting of the
ESnet steering committee.
The opportunity was used for an impromptu
meeting with six members
of the OFES staff to discuss needs for
networking infrastructure by the
fusion program.
Ian Hutchinson, Earl Marmar, and Miklos Porkolab attended
the DOE
budget planning meeting on March 18,19 in Gaithersburg, MD. Ian and
Earl presented the C-Mod
program and plans for FY04-FY05. Miklos
gave
a presentation on PSFC institutional issues. The presentations can be
found at
http://www.psfc.mit.edu/Cmod/sciprogram/CMod_Budget_Meeting_Presentation_03.pdf