Damping of helioseismic modes in steady state

PINTER, B., ERDELYI, R. and NEW, R. (2001). Damping of helioseismic modes in steady state. Astronomy and Astrophysics, 372 (1), L17-L20.

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Link to published version:: 10.1051/0004-6361:20010544

Abstract

The effects of an equilibrium ow in the internal regions of the Sun are studied on the damping of helioseismic f- and p-modes. The Sun is modeled as a multi-layered plasma, where the upper parts, representing the chromosphere and corona, are embedded in a horizontally unidirectional though vertically inhomogeneous magnetic field, while the lower part, representing the sub-photospheric polytropic region, is in a steady equilibrium state. The steady state sub-surface region can be considered as a first approximation of dynamic motions (e.g., differential rotation, sub-surface flows, meridional flows, convective motion, etc.). The frequencies and the line-widths of eigenmodes are affected by sub-surface ow and atmospheric magnetic fields. A key contribution to the effects comes from the universal mechanism of resonant absorption. When both atmospheric magnetic field and sub-surface flows are present, a complex picture of competition between these two effects is found. The theoretically predicted frequency shifts in a steady state show promise of explaining the observed effects. Changes in damping of f- and p-modes caused by changes (e.g. cyclic, if any) of steady state flows are predicted.

Item Type: Article
Research Institute, Centre or Group: Materials and Engineering Research Institute > Thin Films Research Centre > Nanotechnology Centre for PVD Research
Identification Number: 10.1051/0004-6361:20010544
Depositing User: Ann Betterton
Date Deposited: 17 May 2010 17:22
Last Modified: 17 May 2010 17:22
URI: http://shura.shu.ac.uk/id/eprint/2079

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