From: irby@PSFC.MIT.EDU
Reply-To: IRBY@PSFC.MIT.EDU
Subject: Alcator C-Mod Weekly Highlights


Alcator C-Mod Weekly Highlights
February 28, 2003


Work continued on invessel installations, the Lower Hybrid MIE Project, and
ICRF systems. Upgrades to the data system are proceeding.


Physics
-------

Based on an extensive database developed from discharges between 1996
and 1999, a strong correlation has been established between the plasma
stored energy increase (normalized to the plasma current) and the core
toroidal rotation velocity increase after the H-mode transition for both
ICRF and Ohmic plasmas with no external momentum input. The rotation
velocities during the 2002 campaign are 20 to 30% higher for a given stored
energy increase compared to the established trend. Unless the discharge
characteristics have recently changed, it appears that in 2002 the plasma
stored energy as measured by the magnetics is being underestimated by
this same amount, consistent with independent kinetic-magnetic comparisons.
Since the rotation database involves changes in the stored energy after
the H-mode transition, it is implied that the stored energy is
underestimated by a scale factor, and not an offset.


Operations
----------

On Friday the entire C-Mod data archive was relocated to a linux
server. In addition, all of our CAMAC serial highways have been moved
from an OpenVMS server to a linux server. Everyone has been
encouraged to begin testing their data acquisition systems and
analysis programs to make sure they are linux compatible as soon as
possible. During the next few weeks, we will fully test the C-Mod data
acquisition system including the operator machine cycle applications,
shot cycle announcement system, and the plasma control system console
(PCS) in preparations for the next C-Mod run campaign.

We continue installation of the new control coils. Six out of eight
coils are now installed on the igloo.


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

D-Port antenna feedthroughs and antenna straps have been installed
invessel (E-Port installation was completed last week). The J-Port
support plate has been copper plated and baked and will be installed
invessel next week.

We continue work on transmitter control and protection system
upgrades.


LH MIE Project
--------------

At PPPL, the LHCD high power phase shifters have been tested
successfully for VSWR and phase delay. The standard waveguide loops
are also being checked. Removal of braze material from the vacuum
side around the ceramic windows of the antenna front end is now 75%
complete. Alignment of the port extension has been completed, and the
vacuum waveguide assembly will be inserted prior to test stand
installation.

At MIT, work continued on the amplitude and phase control system.
The HVPS and crowbar tests into the dummy load are complete, and high
power testing of the klystrons will begin next week.


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

Significant progress was realized this week at MIT on component
fabrication and testing for the upgraded MSE glass mirror system.
Outside vendors delivered four of six required pieces of the mounting
hardware, with delivery of the final two pieces expected next week.
We successfully completed final cutting of two replacement mirrors on
a waterjet, as well as four test glass blanks and two test backplates
for shake testing.


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

Miklos Porkolab attended the VLT PAC meeting in San Diego. This was his
last attendance, MIT will be represented by Jeff Freidberg in the
future. Jeff has also taken on the role of VLT PAC Chair.

Earl Marmar attended the meeting of the Next Step Options Program
Advisory Committee held at General Atomics in San Diego.