Alcator C-Mod Weekly Highlights
                  June 20, 2011


FY2011 weeks of research operations
Target: 15 weeks
Completed: 14.5 weeks
Plasma Shots: 1706


Physics
-------

Matt Reinke, who is currently completing his PhD in the MIT Nuclear
Science and Engineering Department, has been awarded a two year
DOE-ORISE Postdoctoral Fellowship to continue working on Alcator C-Mod.
The proposed research is aimed at improving our understanding of
impurity seeded (Ne,N2) plasmas by measuring the 2D (radial/poloidal)
power loss layer in the pedestal region due to radiation and charge
exchange.  One important question to answer is how the non-trace level
impurities (~1-2%) impact the pedestal regulation mechanisms in enhanced
confinement discharges, including H-mode and I-mode.


Operations
----------

Early last week we re-installed the limiter tiles on the D and E-port
ICRF antennas following ultrasonic cleaning of the tiles.  The flux loop
on the outer wall between H and J-port was removed for refurbishment,
and to prepare for the installation of studs for the new ARRA funded
rotated antenna.  Studs were removed from the outer wall between G and
H-port in preparation for installation of the Quasi Coherent Mode (QCM)
antenna.  Other divertor and inner wall components which were removed
for cleaning, or because of the need to reach cabling and probes, are
being re-installed.

A load and short circuit study of the EF2 supply is being conducted in
preparation for transferring the EF2 supply feed from the electric
utility sub-station to the alternator.

Many components needed for the QCM antenna are now in-house and are
being prepared for silver or tungsten disulfide coating.  Antenna tiles
are being prepared for baking.


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

Work continued on the ARRA funded rotated antenna.  Three of five
bellows tubes have been plated.  The current strap and strip line
components have been sent out for plating after proper positioning of
these components on the test stand was verified.  Two of the four boxes
that support the Faraday screen rods have been installed on the test
stand successfully and accepted.  Each box holds 19 Faraday rods.  We
continue to prepare the resistive washers and Faraday rods for
installation.


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

Drawings of the new LH limiter support and tiles were sent out for
mock-up production via stereolithography (SLA).  The mock-up pieces will
be test fit in-vessel before manufacturing the final components.

At a review of the LH control system with local and PPPL participation,
a decision was made to replace the vector modulators with discrete phase
and amplitude control components.  Also during the review, a discussion
of the Transmitter Protection System (TPS) indicated all components will
be in-house this summer, with installation expected to take
approximately 2 months.


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

Igor Bespamyatnov, Ken Liao, and Bill Rowan, U Texas, Austin, are
developing a new protective shroud for the window on the poloidal
periscope for the WideView CXRS. This window was partially coated during
the last campaign. In-situ calibration methods permit the calibration to
be updated during the campaign (to provide absolute boron or helium
density measurements, for example), but the coating does reduce signal
level. The existing shroud will be modified by closing off all but the
area actually used by the optical path viewing the DNB.


Travel and Visitors
-------------------

Jon Tester, U.S. Senator from Montana, visited the PSFC on Monday, 6/13,
for a tour of the Alcator C-Mod facility.  The Senator sits on the
Energy and Water appropriations subcommittee.  On the same day, we had a
visit from Gene Karpinski, president of the League of Conservation
Voters. Both visitors were interested in the prospects for, and
environmental impact of, fusion energy.

Willy Burke traveled to PPPL last Friday to serve as an outside reviewer
of the preliminary design of the NSTX Digital Coil Protection System.

David Mikkelsen, PPPL, was at MIT all last week to discuss GYRO
simulations of C-Mod plasmas, to demonstrate use of the new modeling
analysis server, and to install GYRO tools on the server.

Randy Wilson, PPPL, visited last week and participated in the Lower
Hybrid Control System review.

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