Alcator C-MOD Weekly Highlights
				Jan. 20, 1994

The scheduled maintenance period is continuing. This week saw progress in a
number of areas. 

The vacuum pumping station was re-installed on H-port this week. The roughing
pumps still need to be installed, after which the ECE and McPherson
diagnostics can be moved back into operating position. In addition, we
continued installation of inner flange blankets, and the attachment of
insulation to the port boots.  The blankets and boots must be installed on the
machine before we can raise the cryostat, after which heaters, cable trays,
and other equipment below the cyrostat can be re-installed.  C-port extension
has been re-installed and its secondary seal pumped down successfully. The 
secondary seal pressure signal is being used as a test signal for the new PLC
monitoring program.

The LN2 feedline emergency backup lines are nearing completion. Most of the
fitup and welding work is now done, and components are being installed on the
bus tunnel.  Final installation of the feedline into the cryostat must wait
until the cryostat is raised into position.

Thirteen EF1-lower tile modules have now been installed in the vessel, along
with six outer divertor modules.  Twelve floor tile modules are now ready for
installation with all inspection, cleaning, and torquing operations completed.
Several upper EF1 modules are now being prepared for installation.
	
Copper bus components for the TF crowbar bypass cabinets have now been
fabricated and are ready for installation.  The bus work as provided by
Robicon was not considered acceptable for high current operation.  The TF
switch has also been modified to improve its bracing and current handing
capability.  

Machining of all major components for the modification to the ICRF dipole
antennas has now been completed. 

Considerable effort has been put into determining the direction and severity
of disruptions during the last run period.  We found that during the last
month of operation, 90% of the disruptions went down.  These disruptions were
also in general considerably more severe, having on average twice the plasma
current. These results are consistent with our finding nearly all the damaged
tiles in the bottom of the machine.  The results of this work will be added to
the disruption database.

Dr. Karl Lackner of IPP-Garching visited MIT on Friday, Jan. 14, for
discussions on collaborations between Alcator C-MOD and Asdex Upgrade in the
area of non-dimensional similarity experiments. C-MOD and Asdex-U should
produce plasmas with nearly identical dimensionless parameters (beta, nu-star,
rho-star, q, elongation, aspect ratio) but with very different absolute
parameters. Therefore, comparisons of results from the two machines will allow
testing of non-dimensional scaling concepts. Specific topics on which
comparisons will be carried out include confinement, sawtooth period, H-mode
threshold, and disruption behavior (thermal quench time scale).