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Methods In Helio- And Asteroseismology [Kõva köide]

(Imperial College London, Uk)
  • Formaat: Hardback, 320 pages
  • Ilmumisaeg: 11-Dec-2006
  • Kirjastus: Imperial College Press
  • ISBN-10: 1860947557
  • ISBN-13: 9781860947551
Teised raamatud teemal:
Methods In Helio- And AsteroseismologySuurem pilt
  • Formaat: Hardback, 320 pages
  • Ilmumisaeg: 11-Dec-2006
  • Kirjastus: Imperial College Press
  • ISBN-10: 1860947557
  • ISBN-13: 9781860947551
Teised raamatud teemal:
Püsilink: https://www.kriso.ee/db/9781860947551.html
This book discusses the methods used in helio- and asteroseismology for the collection, analysis and interpretation of data. It is the first comprehensive discussion of helioseismic and asteroseismic methodology, collecting techniques from over 300 research papers spread out over decades, with a critical discussion and inter-comparison. It enables the reader to follow the path of inference from the collection of the data at the telescope through to the understanding gained in terms of the modeling of solar and stellar physics and stellar evolution.By focusing on how results are obtained, rather than on the results themselves, this book provides the essential background needed to understand this field, which is rapidly advancing due to the availability of modern observing facilities both on the ground and in space. The material is accessible for advanced undergraduates and post-graduates, and provides an essential resource for researchers in the field.
Preface vii
1. Global Helioseismology: The Data 1
1.1 Intensity Variations
2
1.2 Velocity Variations
4
1.3 From Time-Series to Frequencies
9
1.4 Mode Ambiguities and Cross-Talk
17
1.5 Line Profile Asymmetries
22
1.6 Oscillations at High Frequencies
25
2. Global Helioseismology: Modelling 29
2.1 Separation of Time Scales
30
2.2 Equations of Hydrostatic Structure
32
2.3 Evolution of the Sun and Stars
38
2.4 Numerical Solution Techniques
41
2.4.1 Discretisation of a continuous potential
43
2.4.2 Discretisation in the presence of a discontinuity
47
2.5 The Resonances of Simple Systems
51
2.5.1 Resonant properties of some simple systems
54
2.5.2 Example I: Linear waves in a rectangular membrane
55
2.5.3 Example II: Linear waves in a circular membrane
57
2.5.4 Example III: Linear waves in a uniform sphere
58
2.6 Resonant Frequencies of the Sun and Stars
61
2.6.1 Derivation of the LAWE
61
2.6.2 Boundary conditions
68
2.7 Oscillations in the Cowling Approximation
69
2.8 JWKB Analysis
74
2.9 Surface Effects
79
2.10 Excitation and Damping of Modes
81
3. Global Helioseismology: Inverse Methods 85
3.1 The Relationship between Frequencies and Sound Speed
87
3.1.1 Derivation of the variational structure kernels
94
3.1.2 Filtering out surface effects
100
3.2 The Abel Transform
102
3.3 The Relationship between Frequencies and Rotation
106
3.4 Linearisation
112
3.5 Linear Methods
114
3.5.1 Regularised least-squares
114
3.5.2 Optimally localised averages
116
3.6 Choosing Regularisation Weighting
120
3.7 Non-Linear Methods
123
3.7.1 The maximum entropy method
123
3.8 Optimal Mask Design as an Inverse Problem
127
4. Local Helioseismology 131
4.1 The Data: Reduction and Analysis
131
4.1.1 Tracking, cross-correlation and filtering
132
4.1.2 Averaging and masking
139
4.2 The Forward Approach: Modelling
145
4.2.1 Hydrodynamical models with radiation
145
4.2.2 The influence of magnetic fields
147
4.2.2.1 Dynamo action
149
4.2.3 Turbulence
152
4.2.4 Wave propagation in inhomogeneous media
156
4.2.4.1 Example I: Scattering on a sphere in a homogeneous medium
157
4.2.4.2 Example II: Scattering on an infinite cylinder in a homogeneous medium
163
4.2.4.3 More general scattering proldems
164
4.3 Inverse Methods
166
4.3.1 Ring diagrams
166
4.3.2 Time-distance techniques
171
4.3.3 The ray approximation
172
4.3.4 The Born approximation
177
4.3.5 The Rytov approximation
183
4.3.6 Acoustic holography
187
4.3.7 Seismology of magnetic loops
190
5. Asteroseismology 195
5.1 The Data
196
5.1.1 Signal and noise in the observations
200
5.1.2 The mode identification problem
208
5.1.3 Irregular sampling
220
5.1.4 Non-seismic constraints
227
5.2 Modelling
230
5.2.1 The ages of stars
236
5.2.2 The composition of stars
238
5.2.3 Pulsation of stars
243
5.2.4 Excitation
245
5.2.5 Rotation
246
5.3 Inverse Methods
254
5.3.1 Time-series analysis as an inverse problem
254
5.3.2 Linear and global methods
261
5.3.3 Detecting discontinuities and kinks
268
5.3.3.1 Example: Explicit calculations for a crude model
269
5.3.3.2 Derivative discontinuities in realistic models
274
Appendix A Useful Vector Formulas 279
Appendix B Explicit Forms of Vector Operations 281
Appendix C Useful Constants 287
Bibliography 291
Index 305