The influence of the internal structuring of coronal loops on the properties of their damped transverse oscillations
Inigo Arregui Submitted: 2007-02-08 07:37
The geometry and physical conditions in solar
coronal loops are complicated and still not well
understood. Recent high resolution
observations, obtained with TRACE, indicate the existence of sub-resolution
transverse structuring, not accessible to direct
observation. This ingredient has not yet been
taken into account in previous theoretical
models used for the study of transversal coronal
loop oscillations and their damping due to
resonant conversion of energy.
This study aims to assess the effect of the
possibly unresolved internal structure of a coronal loop on
the properties of its transverse oscillations and on the
efficiency of resonant absorption as a damping mechanism of these
oscillations. The equilibrium configuration of a single
coronal loop with internal density structuring is
modelled by considering the loop as being
composed by two very close parallel identical coronal slabs in Cartesian geometry.
The period of the oscillation and the damping
time, for the resonantly damped fundamental
kink mode, are computed. These quantities are then compared to those obtained
for two models for a single equivalent slab without internal density structuring.
We find that the period and the damping time of
a coronal loop with internal density structuring
change by less than 15%, when compared to the
same oscillatory properties of a single coronal
loop with either the same density contrast or a single coronal
loop with the same total mass.
Therefore the internal density structuring of a coronal loop does not
affect very much its oscillatory properties. However, the sub-resolution structuring of a
coronal loop, with different densities in its
components or with different widths could vary these results.
Authors: I. Arregui, J. Terradas, R. Oliver, & J.L. Ballester
Publication Status: A&A, Vol. 466, 1145-1151 (2007)
Last Modified: 2007-04-26 02:46