Static and Impulsive Models of Solar Active Regions
Spiros Patsourakos Submitted: 2008-08-21 13:24
The physical modeling of active regions (ARs) and
of the global coronal
is receiving increasing interest lately. Recent attempts to model ARs
using static equilibrium models were quite successful in
reproducing AR images of hot soft X-ray (SXR) loops.
They however failed to predict the bright EUV warm loops
permeating ARs: the synthetic images were dominated by
intense footpoint emission.
We demonstrate that this failure
is due to the very weak dependence
of loop temperature on loop length which cannot simultaneously
account for both hot and warm loops in the same AR.
We then consider time-dependent
AR models based on nanoflare heating. We demonstrate that such
models can simultaneously reproduce EUV and SXR loops in ARs.
Moreover, they predict radial intensity variations consistent with the
localized core and extended emissions in SXR and EUV AR observations
respectively. We finally show how the AR morphology
can be used as a gauge of the properties
(duration, energy, spatial dependence, repetition time)
of the impulsive heating.
Authors: S. Patsourakos, J. A. Klimchuk
Publication Status: ApJ, 2008, in press
Last Modified: 2008-08-22 13:37