Combined Modeling of Acceleration, Transport, and Hydrodynamic Response in Solar Flares: I. The Numerical Model |
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Wei Liu Submitted: 2009-06-13 00:52
Acceleration and transport of high-energy particles and fluid dynamics of atmospheric plasma are interrelated aspects of solar flares, but they were artificially separated for simplicity in the past. We present here self-consistently combined Fokker-Planck modeling of particles and hydrodynamic simulation of flare plasma. Energetic electrons are modeled with the Stanford unified code of acceleration, transport, and radiation, while plasma is modeled with the NRL flux tube code. We calculated the collisional heating rate from the particle transport code, which is more accurate than those based on approximate analytical solutions. We used a realistic spectrum of injected electrons provided by the stochastic acceleration model, which has a smooth transition from a quasi-thermal background at low energies to a nonthermal tail at high energies. The inclusion of low-energy electrons results in relatively more heating in the corona (vs. chromosphere), a larger downward conductive flux, and thus a stronger chromospheric evaporation than obtained in previous studies, which had a deficit in low-energy electrons due to an arbitrarily assumed low-energy cutoff. The energy and spatial distributions of energetic electrons and bremsstrahlung photons bear signatures of the changing density distribution caused by chromospheric evaporation. In particular, the density jump at the evaporation front gives rise to enhanced emission, which, in principle, can be imaged by X-ray telescopes. This model can be applied to investigate a variety of high-energy processes in solar, space, and astrophysical plasmas.
Authors: Wei Liu, Vahé Petrosian, and John T. Mariska
Projects: Hinode/SOT,RHESSI
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Publication Status: ApJ (2009 September 10, vol 702, p. 1553-1566, online first August 24)
Last Modified: 2009-08-24 10:32
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