Alcator C-Mod Weekly Highlights
                 March 16, 2009

FY2009 weeks of research operations:
  Target: TBD
  Completed:  0 weeks


Operations
----------

Hi-Pot and AC ring tests of the TF magnet were successfully completed
last week.  These were the last tests required before installation of
the retaining cylinder.  Following these tests, new insulating end caps
that protect the sliding joints were installed, but these were found to
need some re-machining to bring them into specification.  They have now
been put back in place, and we expect to install the cylinder early this
week.

We continued tests on material from the ring samples taken from the
alternator rotor core.  Tests thus far, primarily from the collector end
of the rotor, have indicated good material properties, including
fracture toughness.  We will continue testing this week with samples
taken from both the collector and turbine end of the rotor.  Tensile,
fracture toughness, and crack growth tests will be made.  In addition,
we will continue scanning electron microscope analysis of thin slices of
material as well as fracture surfaces from tested specimens.


Lower Hybrid System
-------------------

We continued simulation work of components that will be used in the 2nd
launcher feed system to ensure that they can run at 250 kW power levels.
Work continued on new control system hardware and software, and the
design of the rf probe electronics.  Lookup tables are being developed
for calculating phase and amplitude information from the probe signals.


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

We continued work on the ICRF control system upgrade.  Ethernet
connections to control system boards are being developed.  Changes to
FMIT#3 are being made to allow independent testing of the driver stage.
This change involves the addition of interlocks and lock-outs for the
final power amplifier stage (FPA).


Diagnostics
-----------

A. Dominguez visited PPPL from March 2 to 6 to work with G. Kramer and
C. Kung on the 130/140 GHz correlation reflectometer for C-Mod.  Antenna
patterns for the new horn antennas were measured.  The system
performance was studied using a mock-up of the antenna system, and
curved mirrors were used to simulate the plasma reflection layers.
Strong reflections were found from curved mirrors at the expected plasma
location and from a flat mirror at the back wall location.  Hardware
from the 110 GHz channel was also integrated into the PPPL system.  Some
rf cross-talk between the two systems was found and work is under way to
resolve this issue.  The antenna patterns were found to be well
collimated in the toroidal and poloidal directions.


Travel and Visits
-----------------

Rick Moyer, UCSD, gave a PSFC seminar on recent results from ELM control
experiments in DIII-D using resonant magnetic perturbations. Rick also
met with a number of C-Mod staff and students for discussions of plasma
surface interactions, edge transport physics and Langmuir probe
hardware.

Earl Marmar visited Columbia University last week, where he gave the
Plasma Physics Colloquium on Recent Results and Plans for Alcator
C-Mod. He also had discussions with Mike Mauel, Amiya Sen and Thomas
Pedersen.

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