  X-ray and EUV observations are an important diagnostic of various plasma
parameters of the solar atmosphere during solar flares. Soft X-ray and EUV
observations often show coronal sources near the top of flaring loops, while
hard X-ray emission is mostly observed from chromospheric footpoints. Combining
RHESSI with simultaneous SDO/AIA observations, it is possible for the first
time to determine the density, temperature, and emission profile of the solar
atmosphere over a wide range of heights during a flare, using two independent
methods. Here we analyze a near limb event during the first of three hard X-ray
peaks. The emission measure, temperature, and density of the coronal source is
found using soft X-ray RHESSI images while the chromospheric density is
determined using RHESSI visibility analysis of the hard X-ray footpoints. A
regularized inversion technique is applied to AIA images of the flare to find
the differential emission measure (DEM). Using DEM maps we determine the
emission and temperature structure of the loop, as well as the density, and
compare it with RHESSI results. The soft X-ray and hard X-ray sources are
spatially coincident with the top and bottom of the EUV loop, but the bulk of
the EUV emission originates from a region without co-spatial RHESSI emission.
The temperature analysis along the loop indicates that the hottest plasma is
found near the coronal loop top source. The EUV observations suggest that the
density in the loop legs increases with increasing height while the temperature
remains constant within uncertainties.
