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arXiv · 0707.0830

A New Look at Mode Conversion in a Stratified Isothermal Atmosphere

A. M. D. McDougall·A. W. Hood
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Abstract

Recent numerical investigations of wave propagation near coronal magnetic null points (McLaughlin and Hood: Astron. Astrophys. 459, 641,2006) have indicated how a fast MHD wave partially converts into a slow MHD wave as the disturbance passes from a low-beta plasma to a high-beta plasma. This is a complex process and a clear understanding of the conversion mechanism requires the detailed investigation of a simpler model. An investigation of mode conversion in a stratified, isothermal atmosphere, with a uniform, vertical magnetic field is carried out, both numerically and analytically. In contrast to previous investigations of upward-propagating waves (Zhugzhda and Dzhalilov: Astron. Astrophys. 112, 16, 1982a; Cally: Astrophys. J. 548, 473, 2001), this paper studies the downward propagation of waves from a low-beta to high-beta environment. A simple expression for the amplitude of the transmitted wave is compared with the numerical solution.

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A. M. D. McDougall, A. W. Hood. 2007-07-05. A New Look at Mode Conversion in a Stratified Isothermal Atmosphere. https://doi.org/10.1007/s11207-007-0393-5

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