Alcator C-Mod Weekly Highlights
			Nov 7, 2005

FY2006 weeks of research operations:
   Planned: 12 weeks (tentative)
   Completed: 0.2 weeks

Operations
----------

Alcator C-Mod resumed plasma operations last week, following the manned-access
vent in September-October. Five days of machine operations, including power
system tests and startup and conditioning activities, were scheduled and
completed.  A total of 59 plasma discharges were produced, with an overall
startup reliability of 48%.

Power system tests were successfully completed on Monday, followed by initial
plasma operations beginning about 3:30 PM. Plasma startup and conditioning
operations continued Tuesday, with full length (2sec) plasmas with current up
to 1.2MA being produced. Plasma cleanliness and startup reliability continued
to improve throughout the week.  In addition, the hydrogen fraction, which is
important for ICRF minority heating, decreased from initial values of H/D~0.5
to H/D<0.2 on Friday.

While continuing to condition the tokamak and auxiliary systems, and bring
diagnostic systems back online, we also began work on the research program,
with much of Friday's run being devoted to evaluation of the operation of the
re-configured J-port ICRF antenna with no Faraday screen.

Plasma operations are planned to continue next week.

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

All three ICRF antenna systems (four transmitters) were operational during
last week's runs. Conditioning of the antennas to full power is proceeding
well. The D-port antenna has operated up to 1.1MW, and E-port up to 1.3MW.

The J-port four-strap antenna, which is being operated for the first time with
the Faraday screen removed, successfully operated up to a maximum power of 3MW
for short pulses (20 ms) and to 2.5MW for 0.2sec. These power levels were
reached without significant impurity injections. This result already marks a
significant step in the process of evaluating the performance of the antenna
in the screen-less configuration, which will be a focus of the ICRF research
program over the next months.

While plasma conditions, in particular the H minority fraction, are still not
optimal for ICRF heating, some plasma heating was observed, and ICRF-induced
H-modes were obtained.

Long Pulse Diagnostic Neutral Beam Systems
------------------------------------------

The DNB system was brought back into operation last week, firing 50ms pulses
at currents up to 6.5Amps into the tokamak.

Work is continuing on the beam interlock system which is required before
operating the DNB with long pulses into the tokamak.

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

Work continues on the current sensor shielding enclosure, which will reduce
the stray magnetic field sensitivity of the klystron body current monitors. A
design review for modifications to the body current measurement circuitry was
held, and one option selected from three proposals. Fabrication and
procurement for implementing the modifications are proceeding.

The #1,#2, and #3 24-window stainless steel couplers have all been
successfully brazed.  All windows were leak-checked and verified to be
vacuum tight. All of the couplers had good braze flow and will require little
cleanup before installation on the launcher. Brazing of the ceramic windows
into the fourth coupler is underway.

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

Earl Marmar and Bruce Lipschultz travelled to GA last week to participate in
the November 1-2 Fourth IEA Large Tokamak Workshop (W62) on "Implementation of
the ITPA Coordinated Research Recommendations", a Joint Workshop of the
Large Tokamak, Poloidal Divertor and TEXTOR Implementing Agreements. Heads of
the major tokamak experimental programs from around the world met with
representatives of the ITPA topical groups to discuss the coming year's plans
for coordinated joint experiments involving run-time on two or more tokamak
facilities.