Analysis and Modeling of Continuous Heating and Long Lasting Outflow in a Flare Observed by AIA and EIS

We analyze and model a C4.7 two-ribbon flare observed by SDO/AIA and Hinode/EIS on 2011 February 13 to investigate how flare loops are heated and evolve. From AIA observations, we can identify two loop systems. EIS Doppler-shift observations reveal blueshifts at the feet of both sets of loops, followed by redshifts. The evolution and dynamics of the two sets are quite different. The first set of loops exhibit buleshifts (~10 km/s) for about 25 minutes, while the second set shows stronger blueshifts (~20 km/s), which are maintained for about 1 hour. The long-lasting blueshifts in the second set of loops are likely due to continuous heating, and this is evident in the UV 1600 observation by AIA showing that the feet of the loops brighten twice with 15 minutes apart. We apply the method of Qiu et al. (2012) to construct heating functions of the two sets of loops using spatially resolved UV light curves from their foot-points, and model plasma evolution in the two sets of loops with the EBTEL model (Klimchuk et al. 2008). Our preliminary analysis of the first loop system shows that the synthetic EUV light curves from the model compare favorably with observed light curves in AIA six channels and EIS eight spectral lines: they show the same evolution trend and their magnitudes are comparable within a factor of two. We also compare the computed mean enthalpy flow velocity with the Doppler shift measurements by EIS: the magnitudes are comparable and the turn-over from upflow (chromospheric evaporation) to downflow (coronal condensation) occurs around the same time. We will apply the observed twice-heating in modeling the second loop system, and examine whether the continuous heating produces long-lasting strong blueshifts consistent with observations.