EDP Sciences
Free Access
Volume 419, Number 3, June I 2004
Page(s) 1149 - 1158
Section The Sun
DOI https://doi.org/10.1051/0004-6361:20041088-1

A&A 419, 1149-1158 (2004)
DOI: 10.1051/0004-6361:20041088

Radiative hydrodynamic modeling of the Bastille-Day flare (14 July, 2000)

I. Numerical simulations
D. Tsiklauri1, M. J. Aschwanden2, V. M. Nakariakov3 and T. D. Arber3

1  Joule Physics Laboratory, School of Computing, Science & Engineering, University of Salford, Salford M5 4WT, UK
2  Lockheed Martin, Advanced Technology Center Solar & Astrophysics Laboratory, Dept. L9-41, Bldg. 252 3251 Hanover Street, Palo Alto, CA 94304, USA
3  Physics Department, University of Warwick, Coventry CV4 7AL, UK

(Received 23 January 2004 / Accepted 26 February 2004)

A 1D loop radiative hydrodynamic model that incorporates the effects of gravitational stratification, heat conduction, radiative losses, external heat input, presence of helium, and Braginskii viscosity is used to simulate elementary flare loops. The physical parameters for the input are taken from observations of the Bastille-Day flare of 2000 July 14. The present analysis shows that: a) the obtained maximum values of the electron density can be considerably higher ( 4.2  $\times$ 1011 cm -3 or more) in the case of footpoint heating than in the case of apex heating ( 2.5  $\times$ 1011 cm -3); b) the average cooling time after the flare peak takes less time in the case of footpoint heating than in the case of apex heating; c) the peak apex temperatures are significantly lower (by about 10 MK) for the case of footpoint heating than for apex heating (for the same average loop temperature of about 30 MK). This characteristic would allow to discriminate between different heating positioning; d) in both cases (of apex and footpoint heating), the maximum obtained apex temperature  $T^{{\rm max}}$ is practically independent of the heating duration  $\sigma_{t}$, but scales directly with the heating rate  $E_{{\rm H0}}$; e) the maximum obtained densities at the loop apex, $n_{\rm e}^{{\rm max}}$, increase with the heating rate  $E_{{\rm H0}}$ and heating duration  $\sigma_{t}$ for both footpoint and apex heating. In Paper II we will use the outputs of these hydrodynamic simulations, which cover a wide range of the parameter space of heating rates and durations, as an input for forward-fitting of the multi-loop arcade of the Bastille-day flare.

Key words: Sun: flares -- Sun: activity -- Sun: corona

Offprint request: D. Tsiklauri, D.Tsiklauri@salford.ac.uk

© ESO 2004