Thermal plasma conditions in the TRACE FeXXIV region

Participants:

Dennis, Caspi, Fletcher, Hudson, McTiernan, Nitta, Sato, Shibasaki ...

Prospectus:

The April 21 flare gives us an opportunity to compare three views 
of the emission-measure distribution in the region above the flare
arcade: the RHESSI low-energy spectra, the TRACE response to the
FeXXIV line at 192A, and the Nobeyama 34 GHz flux. The latter 
depends upon temperature only as the square root, so in this sense
it "calibrates" the emission-measure comparisons between RHESSI
and TRACE by integrating the DEM. The FeXXIV response depends upon 
ionization fraction and Fe abundance, as well as DEM. The plan is
to compare these three items and try to extract enough information
to help with understanding the heating process, even including
the physics. The comparisons will be done across the image field
to the extent possible.

This work should extend to cover a fuller sample of simultaneously-observed
events, say about ten if possible.

Action items:

* Determine RHESSI spectra within the source region (Dennis, Hudson, Sato)
* Determine 34 GHz emission-measure distribution (Shibasaki) 
* Determine FeXXIV emission-measure distribution (Caspi, Fletcher, McTiernan,
  Nitta)
* Make GOES comparisons (Dennis, Hudson, McTiernan)
* Consider the physics of plasma heating (Fletcher, Hudson, Nitta)
* Recruit SUMER colleagues (Hudson)