A&A 420, 699-707 (2004)
DOI: 10.1051/0004-6361:20035725
Properties of longitudinal flux tube waves
II. Limiting shock strength behavior
M. Cuntz1, 21 Department of Physics, Science Hall, University of Texas at Arlington (UTA), Arlington, TX 76019-0059, USA
2 Institute for Theoretical Astrophysics, University of Heidelberg, Tiergartenstraße 13, 69121 Heidelberg, Germany
(Received 21 November 2003 / Accepted 16 March 2004)
Abstract
We extend our previous work on analytic evaluations of properties of
longitudinal tube waves to waves propagating in gravitational atmospheres.
We derive an expression for the limiting shock strength and discuss the behavior
of the shock strength in tubes of different geometry. It is found that a
height-independent value for the limiting strength is attained for
constant cross-section tubes and exponential tubes, whereas for wine-glass
tubes the limiting shock strength increases with height due to the
increase of the tube cross section. The limiting shock
strength is well reproduced by time-dependent simulations.
The derived limiting shock strength
as well as the energy dissipation rate of the waves show significant
similarities to acoustic waves. The limiting shock strength
allows to estimate the heating potential of waves in the
absence of detailed time-dependent computations.
Key words: magnetohydrodynamics (MHD) -- shock waves -- methods: analytical -- Sun: chromosphere -- stars: chromospheres
© ESO 2004

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