Date: Mon, 4 May 1998 20:25:27 -0400
From: IRBY@CMOD.PFC.MIT.EDU
Reply-To: IRBY@PSFC.MIT.EDU
Message-ID: <980504202527.29611524@CMOD.PFC.MIT.EDU>
Subject: Alcator C-Mod Weekly Highlights
Newsgroups: sci.physics.plasma
Organization: MIT Plasma Fusion Center

Alcator C-Mod Weekly Highlights
May 5, 1998



We continue to develop the inductive heating technique for
replacing TF feltmetal. A test fixture with an array of thermocouples
and associated data acquisition equipment has been fabricated and is being
used to determine temperature profiles during the soldering process.
Different coil geometries will also be tried so that an optimized heating
profile can be determined. The TF core has been repositioned on a new
stand so that cleanup and replating activities will be easier to perform.
A detailed survey of feltmetal thickness on the upper and lower horizontal
arm inner joints was finished. The upper horizontal arm feltmetal averaged
.004" thinner than the lower, consistent with the more advanced wear found
there.
We continued to progress in the development of the DNB for C-Mod.
The fault circuitry in the arc/filament/snubber voltage feedback and monitoring
system was completed and calibrated. The breakdown voltage for the oil in
the tank shared by arc/filament/snubber supplies was found to be 20 kV and
conditioning of the oil was begun using the same techniques as for the
accelerator supply and for the Mod/Reg isolation transformer. The design
of the logic boards in the arc/filament/snubber interface to the MCL was
completed. Calibration and testing of the control system for arc detection
was begun. A review of the integration of the beam firing and conditioning
cycle with the C-Mod firing cycle was held to assist in finalizing the
remaining hardware and software required.
We continue to look for the cause of the FMIT#4 crowbar. We have
tested the driver into a dummyload without a fault. This test suggests the
problem is in the final stage. We will begin disassembly midweek for a visual
inspection. If no arc indications are found upon inspection, we will replace
the tube with a spare and test the transmitter again. This change should
allow us to determine if the arc is in the tube or the cavity. We have also
begun testing the control system for FMIT#3. Testing of control boards also
continues.
Martin Greenwald, Ian Hutchinson, Earl Marmar, Spencer Pitcher,
Miklos Porkolab, Joe Snipes, and Steve Wolfe attended the Next Step
Conference in Madison Wisconsin last week. Miklos Porkolab gave a
presentation on ATBX, or Advanced Tokamak Burning Plasma Experiment,
a reduced size, 50% cost, version of ITER.