Alcator C-Mod Weekly Highlights
			November 3, 1997
 

Alcator C-Mod resumed operation last Thursday nearly one week ahead
of schedule with 800 kA, 1-2 X 10^20/m^3 plasmas.  Because the machine has
been under vacuum for several months and an extensive bake and electron
cyclotron discharge cleaning campaign has been carried out, the first plasmas
were clean and had well conditioned walls.  The machine was boronized on
Friday in preparation for RF conditioning and physics operation to begin
Tuesday.  Two days of ECDC in helium was carried out over the weekend to
further condition the new layer of boron.

All alternator systems performed within specification during the
power tests and initial plasma operation.  New instrumentation added to
the alternator to measure rotor current, voltage, and varistor current
is operational, as is a measurement of alternator stator ground current.
Measurements of hi-yard 13.8 kV three-phase current and voltage are
also being added.  The hi-yard measurements will be particularly useful
as we assess the loading to be expected on the grid with the addition of
the new ICRF and lower hybrid systems.

Installation of the high voltage, low capacitance transmission line
between power supplies and the DNB test lab is nearly complete.  Detailed
design for its continuation into the C-Mod Cell began.  Preliminary design
for the modulator/regulator control and instrumentation continued.  Design
of the interfaces between master control logic (MCL) and the PLC and the
MCL and CAMAC was also begun.

Preparation of the 80 MHz RF systems for this run campaign is nearly complete.
The RF was pulsed into one plasma discharge, but it has not yet been properly
tuned.  Shots into vacuum have been taken to test the tuning widget and
processing routines.  The test shots also provided the data needed to determine
some tuning calibration factors.  The determination of two more calibration
factors and final testing of the position feedback circuit must be done
with plasma. Good progress has been made on FMIT#3 and #4 control wiring.
Much of the cross connect wiring has been completed.  This wiring was one of
the biggest remaining jobs.  Fuses and fuse holders for the Uptegraff power
supply were installed last weekend.  This power supply is scheduled
for testing this week.

Norton Bretz from PPPL visited to present his current design for the MSE
optical system.  He also participated in a discussion of various
issues related to implementation of both the MSE and poloidal rotation
diagnostic systems for C-Mod. Gary Taylor and Bob Cutler from PPPL visited to
continue commissioning the new ECE grating polychromator.

Paul Bonoli travelled to  General Atomics last week to participate in
their theory review.

10 Alcator C-Mod abstracts have been submitted for the May Plasma Surface
Interactions Conference.  Another 4 are being sent in by collaborators.
One paper submitted earlier by Jim Terry on his work with recombination and
Lyman series absorption in the divertor plasma has been accepted as an
invited talk.  Other papers are:

(1) 'Electron Cyclotron Discharge Cleaning (ECDC) Experiments on Alcator C-Mod'
Presenting author: R. Nachtrieb

(2) 'Modeling of the Effects of Neutrals on Detachment and Edge Plasma
Transport in Alcator C-Mod'
Presenting author: M. Umansky

(3) 'Molybdenum Erosion Measurements in Alcator C-Mod'
Presenting author: W.R. Wampler

(4) 'Recombination & Ion Loss in C-Mod Detached Divertor Discharges'
Presenting author: B. Lipschultz

(5) 'Scrape-off Layer Impurity Transport and Screening Experiments using a
Novel Tracer-Gas Injection System'
Presenting author: B. LaBombard

(6) 'Empirical Scalings of Cross-Field Diffusivities in the
Scrape-off-Layer of Alcator C-Mod from a 2-D Interpretive Model'
Presenting author: M. Umansky

(7) 'The Roles of Friction and Recombination in SOL Pressure Balance'
Presenting author: C.S. Pitcher

(8) 'Impurity Compression and Enrichment Studies on Alcator C-Mod'
Presenting author: J.A. Goetz

(9) 'Kinetic Study of Thermoelectric Currents in the SOL Plasmas'
Presenting author: O. Batishchev

(10) 'Molybdenum Sources and Sinks in the Alcator C-Mod Tokamak'
Presenting author: D. Pappas