REPORT FROM ISAS
                        16-Mar-94 to 23-Mar-94
                              L. W. Acton

There have been times during the past week when the GOES plot was
absolutely flat and featureless at about an A8 level--yet the SXT images
revealed a wealth of structure, variety of detail and active evolution. 

I'm approaching the end of analyzing some 34,000 SXT images taken over
the past 30 months with the collaboration of H. Hara.  The integrated
x-ray flux (smoothed) has decreased by about a factor of 10 although the
total emission of the faint corona has remained surprisingly stable. 
All of the decrease has been in the bright stuff.  I suppose that no one
will be excited by the fact that I have discovered a very strong 27 day
periodicity?  Of more interest, I've summed all of the clean (non-SAA)
data for the first year of Yohkoh operation for those cases where
pictures were acquired through thin Al and Dagwood within 5 minutes of
one another (1755 cases).  The temperature of the corona measured in
this way is 3.0 MK and the emission measure is 2e49 cm^-3.  This
temperature is biased high, and the emission measure biased low, by the
presence of higher temperature material.  For the same period I derive 
a temperature of 5.6 MK and an emission measure of 1e48 for the bright
cores of active regions.  Fun stuff!

Barry LaBonte continues to study temperatures in some well-observed
post-flare loops at the limb while Hugh Hudson is looking at the
temperature distribution in flares with a super-hot component.  Both of
them seem to be finding that the hotter the temperature the more diffuse
the source.

Karen and Jack Harvey and Greg Slater arrived today.  Len Culhane comes
tomorrow.  Should provide for interesting times.

We have suffered a MAJOR embarrassment this week.  I won't go into the
gory details but it seems ISASS0, our primary computer, has been
squirreling away a random samples of outgoing e-mail for the past 2.5
years and this was all released in a flood this last weekend when Tim
Roethig corrected an error in the mail handling utility.  Our apologies
to those of you who received obscure old messages and also to
individuals who were criticized for not responding to message that never
made it out of ISASS0.