Magnetohydrodynamic kink waves in twodimensional nonuniform prominence threads 

Inigo Arregui Submitted: 20101130 01:48
We analyze the oscillatory properties of resonantly damped transverse kink oscillations in twodimensional prominence threads. The fine structures are modeled as cylindrically symmetric magnetic flux tubes with a dense central part with prominence plasma properties and an evacuated part, both surrounded by coronal plasma. The equilibrium density is allowed to vary nonuniformly in both the transverse and the longitudinal directions. We examine the influence of longitudinal density structuring on periods, damping times, and damping rates for transverse kink modes computed by numerically solving the linear resistive magnetohydrodynamic (MHD) equations. The relevant parameters are the length of the dense part and the density in the evacuated part of the tube, two quantities that are difficult to directly estimate from observations. We find that both of them strongly influence the oscillatory periods and damping times, and to a lesser extend the damping ratios. This information is complemented with the analysis of the spatial distribution of perturbations and the energy flux at the resonances that allow us to explain the obtained damping times. Implications for prominence seismology are discussed in connection to the fact that observations may allow us to measure the length of the thread, while the supporting magnetic flux tube is not even observed and the density in the evacuated part of the tube is also difficult to estimate.
Authors: I. Arregui, R. Soler, J. L. Ballester, A. N. Wright
Projects: None

Publication Status: submitted
Last Modified: 20101201 10:54


