Soft X-Ray Spectroscopy of Solar Flares with RHESSI and GOES

In this work we use data from the RHESSI and GOES spacecraft in an attempt to determine the characteristics of thermal emission during solar flares. Previous attempts to do this have been hampered by the assumption that flare thermal emission has a single temprature. Using RHESSI and GOES (and GOES-SXI) data, we now have a method for calculating the differential emission measure for high temperature flare emission, while accounting for contamination of the spectrum due to the presence of nonthermal emission. This gives a more accurate measure of the amount of energy that is released into high temperature (3 to 20 MK) plasma. As of Feb-2004, there are more than 13000 flares in the RHESSI database with emission above 12 keV. This work will include every flare observed by RHESSI for which it is possible to obtain a spectrum, from microflares to X-class flares.