Incompressible Magnetohydrodynamic Surface Waves: Nonlinear Aspects
Abstract
The nonlinear properties of MHD surface waves in the solar atmosphere are investigated analytically, assuming that the fluid is incompressible and that the waves are confined to a single surface, with semiinfinite regions on both sides. The governing equations are derived in detail, and qualitative results are presented in a graph. For propagating waves, second-order terms in the wave amplitude are found to lead to wave steepening at leading or trailing edges, the steepening rate becoming very large as the threshold for the linear Kelvin-Helmholtz instability is approached. Second-order effects on standing waves include crest and trough sharpening (increasing with time), a current independent of distance on the surface but decreasing exponentially with distance from the surface, and pressure-field fluctuations of infinite extent. It is suggested that these effects could account for a large fraction of solar-atmosphere heating.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1987
- DOI:
- 10.1086/165341
- Bibcode:
- 1987ApJ...317..918H
- Keywords:
-
- Magnetohydrodynamic Waves;
- Solar Atmosphere;
- Surface Waves;
- Kelvin-Helmholtz Instability;
- Magnetohydrodynamic Stability;
- Standing Waves;
- Wave Propagation;
- Solar Physics;
- HYDROMAGNETICS;
- INSTABILITIES;
- SUN: ATMOSPHERE