Institution(s): 1. Nanjing University, 2. Shanghai Astronomical Observatory
Solar flares involve in radiations in very broad wavelengths. Spectra can supply us abundant information about local plasma, such as temperature, density, mass motion and so on. Strong chromosphere lines, like the most studied Hα and Ca II 8542 Å are formed under conditions of non-local thermal equilibrium which represent the response of the lower atmosphere to flare heating. Understanding the line formation is very useful for us to correctly interpret the observations and evolution of line intensities and profiles. Numerical simulation is a very important way to interpret observational data and understand the flare mechanisms. In this paper, we try to figure out the response of chromospheric lines heated by different periodic impulsive non-thermal electrons. Our results are based on radiative hydrodynamic simulations. We vary the non-thermal heating periods from 1.25s to 20s. Different non-thermal electron fluxes are also considered in our simulations. We compare the response times for different heating parameters. Line centers and line wings also show different signatures. Possible explanations are discussed in the paper.
This work is supported by NSFC under grants 11303073 ,11373023 and 11103008. This research is also supported by the open project of Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences.