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


Alcator C-Mod Weekly Highlights
January 11, 1999



The Power Systems Group completed the checkout of the alternator
instrumentation and CAMAC systems last week. All power systems are
now ready for operation. The alternator, which is now on turning gear,
will be brought up to full speed this week and be ready to provide power
for magnet tests late in the week. Our main focus of activity continued to
be the HEAT system last week. Now that the wiring is complete, we are
powering up one set of heaters at a time and verifying proper feedback control.
Completion of this system is now the critical path to plasma operation since
we can not bake the vessel or cool the magnets until the HEAT system is
running reliably.

The modifications for the DNB controls continued. Design of the grid drive
control board for the Mod/Reg is complete. The new chassis to accommodate
the new control electronics for the the Mod/Reg tube is nearing completion
while the low voltage control chassis was completed and installed.

The Core Thomson Scattering system was aligned and calibrated last week.
The machine was backfilled with argon and data was obtained at several
fill pressures. The ECDC system was turned on briefly to verify proper
operation of the new waveguide run. The upper TCI mirror and beamline has
been installed and purged with GN2. Alignment of the TCI system will begin
this week.

We are in the process of connecting and debugging the new Fast MHD coils.
Sixty-two of the 65 coils signals are available, 30 of which have been
connected to 1 MHz sampling digitizers and 6 to 2 MHz sampling digitizers.
Presently, they are connected without amplifiers, which are still in
production. The coils on one limiter were calibrated without amplifiers, and
a resonance was found centered about 700 kHz, which is at the upper limit of
Alfven eigenmodes measured to date. With the amplifiers at the machine end of
the cable, the resonance is expected to shift to still higher frequencies,
outside the range of interest even for these modes, which should allow clear
phase differences to be measured to determine mode numbers.

The Chromex spectrometer system is being checked out through the CAMAC
highway. Calibration of the Reticon arrays and the new filtered diodes
which have views co-linear with the VUV spectrometer have been calibrated.
The midplane fast ionization gauge at G-port has been installed and brought
into operation, as has the new high-sensitivity Barotron gauge at the
same location.


Physics:

The C-Mod Experimental Program Committee approved nine MiniProposals last week
for experiments to be carried out during Start-up Operations. These experiments
are required for alignment and calibration of diagnostics, RF conditioning,
and commissioning of new internal hardware.

Travel and Visits:

During his visit in Denmark over the holidays, Thomas Sunn visited
Risoe National Laboratory on Jan. 5, and gave a talk on
"Edge plasma phenomena measured by the x-ray imaging diagnostic".