Alcator C-MOD Weekly Highlights
				May 19, 1994

Phase II plasma operation has continued this week.  We are still in the
process of re-establishing operation with the new limiter and antenna
geometry. Plasma currents over 800kA are now being produced.  

The connector repair in the magnetics diagnostics system which was reported
last week did not completely solve the problem. Additional diagnostics were
observed to become unreliable as operation continued. The problems were all
found to be related to three connectors on a single flange, and testing
on Friday established that the problem was on the vacuum side. A "clean" vent,
with helium backfill, was performed on Monday. It was found that the three
connectors in question had not been properly installed; this was remedied, and
the vessel pumped back down after approximately four hours.  Subsequently, the
magnetics diagnostic situation has remained stable, with only one flux loop
still excluded from control functions due to intermittancy. Wall conditions
deteriorated somewhat due to the vent, but are again improving.

Tuning and conditioning of the D-port ICRF antenna is proceeding, following a
modification to the four-inch coax sections to reduce arcing. ICRF tuning is
scheduled as a piggyback activity on all runs this week.

The Science Research Laboratories Shearing Interferometer diagnostic, which
observes fluctuations in H-alpha light, has been getting data on the edge
turbulence. At a k-perp of about 15 cm-1, a broadband spectrum with frequency
width of about 100kHz is observed. When the diagnostic is oriented to be
sensitive to k-parallel, no significant signal above the noise level is
observed. At k_perp of 5 cm-1, the signal level is about a factor of 10 higher 
at low frequency, with a slightly narrower frequency spectrum.

The new Bp-coils mounted on the guard limiters are in routine operation. Both
integrated and unintegrated signals are being digitized; the former will be
used in equilibrium reconstructions, while the latter are digitized at high
rates and are used for investigation of MHD phenomena. "Gong" modes,
associated with sawtooth crashes (previously reported on JET), have been
identified. 

S. Moriyama, a scientist from the JT-60U ICRF Group, is visiting Alcator for a
period of two weeks. He is working with the C-MOD ICRF Group.

Contrary to last week's report, Paul Bonoli did not attend the TTF Transport
Workshop, due to other commitments; Miklos Porkolab represented Alcator at the
Workshop.