Observation and numerical modeling of chromospheric evaporation during the impulsive phase of a solar flare

Abstract

We have studied the chromospheric evaporation flow during the impulsive phase of the flare by using the Hinode/EIS observation and 1D hydrodynamic numerical simulation coupled to the time-dependent ionization. The observation clearly shows that the strong redshift can be observed at the base of the flaring loop only during the impulsive phase. We performed two different numerical simulations to reproduce the strong downflows in FeXII and FeXV during the impulsive phase. By changing the thermal conduction coefficient, we carried out the numerical calculation of chromospheric evaporation in the thermal conduction dominant regime (conductivity coefficient kappa0 = classical value) and the enthalpy flux dominant regime (kappa0 = 0.1 x classical value). The chromospheric evaporation calculation in the enthalpy flux dominant regime could reproduce the strong redshift at the base of the flare during the impulsive phase. This result might indicate that the thermal conduction can be strongly suppressed in some cases of flare. We also find that time-dependent ionization effect is importance to reproduce the strong downflows in Fe XII and Fe XV.

15 pages, 10 figures, accepted Physics of Plasma

References in corpus (4)

• Imaging and spectroscopic observations of magnetic reconnection and chromospheric evaporation in a solar flare
• Modelling of EIS spectrum drift from instrumental temperatures
• Combined Modeling of Acceleration, Transport, and Hydrodynamic Response in Solar Flares: I. The Numerical Model
• Modeling properties of chromospheric evaporation driven by thermal conduction fronts from reconnection shocks

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• Intrusion of Magnetic Peninsula toward the Neighboring Opposite-polarity Region That Triggers the Largest Solar Flare in Solar Cycle 24
• Nowcast of an EUV dynamic spectrum during solar flares
• Non-Equilibrium Ionization Plasma During Large Solar Limb Flare Observed by Hinode/EIS
• Energy distribution of small-scale flares derived using genetic algorithm
• Velocity Structure and Temperature Dependence of Extreme-Ultraviolet Jet Observed by Hinode