SDO AIA and EVE observations and modelling of solar flare loops

Abstract

We present imaging and spectroscopic observations of an isolated C1-class solar flare, obtained with the Atmospheric Imaging Assembly (AIA) and Extreme ultraviolet Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO). We obtain excellent agreement between the peak flare temperatures estimated using the EVE spectra with those obtained from GOES and, most importantly, from the ratio of the 94 A and 131 A AIA channels, which are found to be dominated by Fe xviii and Fe xxi .T hese results confirm that these two AIA bands can be reliably used to provide temperature diagnostics for the peak and gradual phases of solar flares. The flare kernels, probable sources of chromospheric evaporation, are seen as strong localised emission in the AIA bands at the footpoints of flare loops. The flare loops are close to isothermal during the gradual phase. We have run several hydrodynamic simulations (using the HYDRAD code) to study the cooling of the flare loops. We find good overall agreement between observed and predicted electron temperatures and densities when a gradual increase and decrease of the heating is assumed.