Alcator C-MOD Weekly Highlights
			June 13,  1995


	Alcator C-MOD is now entering a planned up-to-air period during
which major activities such as installation of our proto-type cryopump
and an edge Thomson Scattering diagnostic will be completed.  However,
our last week of plasma operation included four very interesting run
days during which issues involving transport, divertor detachment, and
RF heating scenarios at high field were investigated.  

	On Tuesday a kappa scan at low density was done and
the effects on tauE noted at nebars of 0.5 and 1.5 e20/m**3.  Initial
analysis indicated a strong increase in tauE with increasing kappa.  A
kappa scan at constant safety factor and low density was also accomplished.
What appeared to be visible synchrotron radiation was observed at low
densities.

	The dependence of the detachment density threshold on plasma current
and q was investigated on Wednesday.  A rather strong scaling of this threshold
with q at fixed current was noted: nl of 1.5e20/m^2 at 3.6 T, 1.2e20/m^2 at
5.3 T, and 1.0e20/m^2 at 7.0 T. This result could be indicative of the
importance of field line length to the interaction of neutrals with ions in
the divertor.  However, much more analysis of SOL and divertor parameters is
needed to properly quantify these results.

	Thursday's run investigated mode conversion, heating, and
transport in hydrogen majority, He3 minority plasmas, at 6.4 T.  The
RF power was modulated at 40 Hz so that energy transport could be
investigated using the ECE polychromator as the primary diagnostic. 
Good heating results were obtained; the heating appeared very sensitive to
both plasma density and He3 fraction.  Some very good modulation results were
obtained, and these data should result in reliable measurements of transport
coefficients when the analysis is completed.  Finally, a circuit designed to
provide a feedback signal proportional to RF loading was tested.   This signal
was successfully used to adjust the plasma position so that constant RF
loading could be obtained.  Such feedback control may become a very
important tool for extending H-mode periods during which large edge
profile changes occur.

	On Friday He3 minority heating in deuterium was investigated at
7.9 T and a plasma current of 1 MA.  Up to 2.3 MW of RF power was coupled
into the plasma, and a wide range of densities were studied (0.8 to 1.5e20/m^2).
In addition, lithium pellets were injected on several shots; the resulting
PEP modes yielded high ion temperatures (3.6 keV), and neutron
rates (8e13/sec) with up to 130 kJ of stored energy.
Another remarkable result of this run was transitions to H-mode confinement
at 8 T and an NL of 1.5e20/m^2, including short ELM-free periods.

	Steve Wolfe participated in the NSTX Validation Review held at PPPL
June 5-7.  John Rice participated in the  11th International Conference in
UV and Xray Spectroscopy of Astrophysics and Lab Plasmas from May 30 to June 2.
John presented a paper on X-ray Observations of High n Transitions in Neon-like
Molybdenum from Alcator C-Mod.  He also visited the LHD site in Toki, Japan.