Alcator C-MOD   
			    Weekly Highlight Report  
				September 16, 1993


Alcator C-MOD has resumed plasma operation after a scheduled three-week
maintenance period.  Operation resumed on Tuesday, September 14.

During the bakeout of the vessel at the end of the maintenance period, it was
discovered that several of the valves controlling the flow of LN2 to the coils
had degraded. The faulty components were all replaced, and cooldown of the
machine proceeded with minimal interruption.  Electron Cyclotron Discharge
Cleaning (ECDC) was carried out for a total of approximately 48 hours. 

Installation of the reactors on the OH1, OH2, and EF1 supplies was completed
on Thursday of last week. Power system tests were carried out on Friday and
Monday, to verify four-quadrant operation of these supplies. In addition, all
other PF supplies were tested individually. Besides verifying that all systems
were ready for operation, the single supply tests were used to evaluate pickup
on the diamagnetic loops. 

The first runs of this campaign are planned to take advantage of the reverse
swing capability to extend the flattop time and increase the plasma current.
The pulse length has been extended to over 0.9 sec, with plasma currents over
0.6 MA. Wall conditions over the first two days of plasma operation appear
marginal, with a high proportion of "fizzles" and disruptive discharges,
particularly following high current disruptions.  

Essentially all of the successful long pulse discharges so far this week have
been single null divertor plasmas with slowly increasing elongation; these are
typically terminated by a vertical disruption. Disruption rates as high as 
1MA/msec have been observed. These experiments are continuing. 

The charge exchange neutral particle analyzer installed at F-port over the
break is operational and producing data.