Alcator C-Mod Weekly Highlights
May 23th, 2011

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


  Physics
  -------

Numerous C-Mod personnel participated in last week's 19th Topical
Conference on Radio-Frequency Power in Plasma, held in Newport
RI. Included in the program were invited oral presentations from two MIT
graduate students, Orso Meneghini ("Effects of SOL on Lower Hybrid Wave
Coupling and Current Drive Performance on Alcator C-Mod") and Naoto
Tsujii ("ICRF Mode Conversion Studies with Phase Contrast Imaging and
Comparisons with Full-Wave Simulations") along with many poster
contributions from C-Mod team members. Presentations and posters can be
found at

http://www.psfc.mit.edu/research/alcator/pubs/RF/rf2011index.html.


Operations
----------

Invessel work last week included refurbishment of the plasma facing
surfaces at several outer divertor locations.  Inner wall tile modules
were removed in preparation for installation of a new gas puff capillary
at B-Port.  Measurements were made to properly size the fiber bundle for
the Fast Ion Loss Detector.

The calibration of the alternator lube oil pressure, float, and
temperature switches was completed last week.


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

FMIT#4 has been returned to its normal configuration
and tested at the 2  MW level into a dummy load following completion of
the rf breakdown  experiments.  The transmitter was then made safe and
routine maintenance  and cleaning of FMIT#4 and #3 continued.  Upgrades
for the anode current  overload sensors are being considered.


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

All Cathode Over Temperature (COT) sensor interface signals were
successfully tested last week.  This system shuts down the klystrons if
an algorithm in the Transmitter Protection System (TPS) predicts the
cathode temperature will go out of range during the lower hybrid pulse.
We continued to work with our vendor on hardware and software for the
TPS.  Cabling for the new control system is being specified and
procured.

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

A. Bader, S.G. Baek, P. Bonoli, I. Faust, M. Garret, J.P. Lee, Y. Lin,
O. Meneghini, R. Ochoukov, R.  Parker, A. Ram, S. Shiraiwa, N. Tsujii,
G. Wallace, J.C. Wright, Randy Wilson (PPPL), K.T. Liao, UT, and
R. Wilson, PPPL, attended the 19th Topical Conference on Radio-frequency
Power in Plasmas that was held in Newport, RI from June 1-3, 2011.  Paul
Bonoli served as a member of the International Program Committee, and
Randy Wilson was Co-Chair.

On May 31st, we hosted a visit by a group from Cadarache and a group
from Frascati. The Cadarache group included Xavier Litaudon, Annika
Ekedahl, Jean-Michel Bernard, Marc Goniche and Tuong Hoang, while the
group from Frascati consisted of Roberto Cesario, Alessandro Cardinali
and Silvio Ceccuzzi.  The topics of discussion spanned Lower Hybrid and
ICRF physics and technology, including the anomalous drop off in lower
hybrid current drive efficiency at high density, now observed in Tore
Supra as well as in C-Mod.  Plans for increased collaborations among the
C-Mod and Tore-Supra teams were also discussed.

On Tuesday, Dr. Litaudon gave the PSFC seminar, entitled "RF physics and
technology activities at IRF".

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