Bibcode
Soler, R.; Arregui, I.; Oliver, R.; Ballester, J. L.
Bibliographical reference
The Astrophysical Journal, Volume 722, Issue 2, pp. 1778-1792 (2010).
Advertised on:
10
2010
Journal
Citations
42
Refereed citations
35
Description
We investigate standing kink magnetohydrodynamic (MHD) oscillations in a
prominence fine structure modeled as a straight and cylindrical magnetic
tube only partially filled with the prominence material and with its
ends fixed at two rigid walls representing the solar photosphere. The
prominence plasma is partially ionized and a transverse inhomogeneous
transitional layer is included between the prominence thread and the
coronal medium. Thus, ion-neutral collisions and resonant absorption are
the damping mechanisms considered. Approximate analytical expressions of
the period, the damping time, and their ratio are derived for the
fundamental mode in the thin tube and thin boundary approximations. We
find that the dominant damping mechanism is resonant absorption, which
provides damping ratios in agreement with the observations, whereas
ion-neutral collisions are irrelevant for damping. The values of the
damping ratio are independent of both the prominence thread length and
its position within the magnetic tube, and coincide with the values for
a tube fully filled with the prominence plasma. The implications of our
results in the context of the MHD seismology technique are discussed,
pointing out that the reported short-period (2-10 minutes) and
short-wavelength (700-8000 km) thread oscillations may not be consistent
with a standing mode interpretation and could be related to propagating
waves. Finally, we show that the inversion of some prominence physical
parameters, e.g., Alfvén speed, magnetic field strength,
transverse inhomogeneity length scale, etc., is possible using
observationally determined values of the period and damping time of the
oscillations along with the analytical approximations of these
quantities.