Book contents
- Frontmatter
- Dedication
- Contents
- Preface
- 1 General Principles
- 2 Waves in a Uniform Medium
- 3 Magnetically Structured Atmospheres
- 4 Surface Waves
- 5 Magnetic Slabs
- 6 Magnetic Flux Tubes
- 7 The Twisted Magnetic Flux Tube
- 8 Connection Formulas
- 9 Gravitational Effects
- 10 Thin Flux Tubes: The Sausage Mode
- 11 Thin Flux Tubes: The Kink Mode
- 12 Damping
- 13 Nonlinear Aspects
- 14 Solar Applications of MHD Wave Theory
- References
- Index
9 - Gravitational Effects
Published online by Cambridge University Press: 15 July 2019
- Frontmatter
- Dedication
- Contents
- Preface
- 1 General Principles
- 2 Waves in a Uniform Medium
- 3 Magnetically Structured Atmospheres
- 4 Surface Waves
- 5 Magnetic Slabs
- 6 Magnetic Flux Tubes
- 7 The Twisted Magnetic Flux Tube
- 8 Connection Formulas
- 9 Gravitational Effects
- 10 Thin Flux Tubes: The Sausage Mode
- 11 Thin Flux Tubes: The Kink Mode
- 12 Damping
- 13 Nonlinear Aspects
- 14 Solar Applications of MHD Wave Theory
- References
- Index
Summary
The effect of gravity is investigated in this chapter and the importance of the Klein-Gordon equation is demonstrated. The Klein-Gordon equation is solved for impulsive initial conditions and the phenomenon of an oscillating wake demonstrated. Cutoff frequency is determined. Waves in a stratified incompressible medium with a horizontal magnetic field are examined, leading to the Rayleigh-Taylor dispersion relation. The compressible case is related to the topic of magnetic helioseismology. Waves in a vertical magnetic field are also discussed. For this case, the slow mode dispersion relation is obtained and exhibits a cutoff frequency.
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- MHD Waves in the Solar Atmosphere , pp. 248 - 280Publisher: Cambridge University PressPrint publication year: 2019