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 4, 2003



The Alcator C-Mod vacuum vessel is currently under bake at 120C. Work
continues on the new non-axisymmetric control coils, Lower Hybrid
Project, and ICRF systems. The flywheel inspection has been
completed.


Operations
----------

The flywheel inspection was completed successfully on Wednesday.
A tomographic UT inspection of the flywheel rotor was done. The
bearings were checked using dye penetrant, magnetic particle, and UT
techniques. Re-assembly of the flywheel is underway.

A bake of the Alcator C-Mod vacuum vessel was begun on Wednesday. The
bake is expected to last until mid next week. ECDC was begun on
Friday evening and will continue up to the point of plasma operation.
A short term schedule of planned operations can be found at

http://www.psfc.mit.edu/cmod/operations/schedule.txt

The new non-axisymmetric control coils were tested to their rated
current of 3000 amps last week. These coils will be used for study and
control of locked modes and error field amplification effects during
the upcoming campaign. Up to four coils in series were driven by a
single supply, with current waveforms prescribed through the C-Mod
Plasma Control System (PCS) interface and the Hybrid Control
Computer. The magnetic configuration (toroidal phase, m/n spectrum,
and helicity) of the control field was varied shot-to-shot using a
patch panel. Stray fields from the igloo-mounted coils were monitored
during the tests, and the adequacy of shielding around the pumping
station turbo-pumps was confirmed. Fields measured by the C-Mod
magnetics diagnostics were consistent with design calculations.


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

The D, E, and J-Port resonant loops have been re-assembled for
operation. The J-Port decoupling stub has been installed and tested.
D and E-port have been connected to the transmitters and initial
testing of the system has been completed, including low power
operation (~40 kW), and verification of voltage and phase balance
protection. D and E-Port vacuum conditioning will begin once the
machine bake has been completed.

Commissioning of the control and fault protection systems is
underway in preparation for the next run campaign.


Lower Hybrid Project
--------------------

At MIT, work continued on bringing up rf power from the klystrons. A
body current fault had been limiting the applied high voltage to about
42 kV. On Friday this fault was tracked down to an arc in the dummy
load. An applied voltage of 47 kV and extracted power of 240 kW was
then obtained (full power specification is 250 kW).

At PPPL, final preparations for shipment of the lower hybrid launcher
were being made. Two C-Mod engineers, Bill Beck and Bob Childs, will
visit PPPL next week to discuss final shipment details.