  One of the defining characteristics of a solar flare is the impulsive
formation of very high temperature plasma. The properties of the thermal
emission are not well understood, however, and the analysis of solar flare
observations is often predicated on the assumption that the flare plasma is
isothermal. The EUV Variability Experiment (EVE) on the Solar Dynamics
Observatory (SDO) provides spectrally resolved observations of emission lines
that span a wide range of temperatures (e.g., Fe XV-Fe XXIV) and allow for
thermal flare plasma to be studied in detail. In this paper we describe a
method for computing the differential emission measure distribution in a flare
using EVE observations and apply it to several representative events. We find
that in all phases of the flare the differential emission measure distribution
is broad. Comparisons of EVE spectra with calculations based on parameters
derived from the GOES soft X-ray fluxes indicate that the isothermal
approximation is generally a poor representation of the thermal structure of a
flare.
