The Sun: An Introduction

1. Characteristics of the Sun.- 1.1 Distance.- 1.2 Mass.- 1.3 Radius.- 1.4 Luminosity.- 1.5 Spectral Energy Distribution.- 1.5.1 Energy Flux and Intensity.- 1.5.2 The Visible.- 1.5.3 The Infrared.- 1.5.4 The Radio Spectrum.- 1.5.5 The Ultraviolet.- 1.5.6 Extreme Ultraviolet and X-rays.- 1.5.7 Color Indices.- 1.6 Bibliographical Notes.- 2. Internal Structure.- 2.1 Construction of a Model.- 2.1.1 The Evolutionary Sequence.- 2.1.2 The Standard Model.- 2.2 Age and Pre-Main-Sequence Evolution.- 2.3 Model Ingredients.- 2.3.1 Conservation Laws.- 2.3.2 Energy Transport.- 2.3.3 Element Diffusion in the Interior.- 2.3.4 The Equation of State.- 2.3.5 The Entropy.- 2.3.6 Nuclear Energy Sources.- 2.3.7 The Opacity.- 2.3.8 Boundary Conditions and Method of Solution.- 2.4 Results for a Standard Solar Model.- 2.4.1 General Evolution.- 2.4.2 Neutrinos.- 2.5 Non-Standard Models.- 2.5.1 The Low-Z Model.- 2.5.2 Rapidly Rotating Core.- 2.5.3 Internal Magnetic Field.- 2.5.4 The Internally Mixed Model.- 2.6 Bibliographical Notes.- 3. Tools for Solar Observation.- 3.1 Limitations.- 3.1.1 General Difficulties.- 3.1.2 Seeing: Description and Definitions.- 3.1.3 Seeing: How to Live with It.- 3.1.4 Adaptive Optics.- 3.1.5 Image Restoration.- 3.2 High-Resolution Telescopes.- 3.2.1 Image Scale.- 3.2.2 Mirrors for Fixed Telescopes.- 3.2.3 Telescopes with Long Primary Focus.- 3.2.4 Telescopes with Short Primary Focus.- 3.3 Spectrographs and Spectrometers.- 3.3.1 The Grating Spectrograph.- 3.3.2 The Fourier Transform Spectrometer.- 3.3.3 The Measurement of Line Shifts.- 3.4 Filters and Monochromators.- 3.4.1 The Lyot Filter.- 3.4.2 Tuning: the Universal Filter.- 3.4.3 A Tunable Michelson Interferometer.- 3.4.4 The Fabry-Perot Interferometer.- 3.4.5 A Magneto-Optical Filter.- 3.4.6 A Double Monochromator.- 3.4.7 The Spectroheliograph.- 3.5 Polarimetry.- 3.5.1 Zeeman Splitting.- 3.5.2 Polarized Light.- 3.5.3 Unno's Equations.- 3.5.4 Solar Polarimeters.- 3.5.5 Scattering Polarization and Hanle Effect.- 3.6 Special-Purpose Instruments.- 3.6.1 The Pyrheliometer.- 3.6.2 Neutrino Detectors.- 3.6.3 The Coronagraph.- 3.7 Bibliographical Notes.- 4. The Atmosphere.- 4.1 Radiative Transfer - Local Thermodynamic Equilibrium.- 4.1.1 The Equation of Transfer.- 4.1.2 Various Equilibria.- 4.1.3 Absorption Lines in LTE.- 4.2 Radiative Transfer - Statistical Equilibrium.- 4.2.1 Model Assumptions.- 4.2.2 Line Radiation and Einstein Coefficients.- 4.2.3 Continuum Radiation.- 4.2.4 Collisions.- 4.2.5 The Source Function.- 4.2.6 The Equations of Statistical Equilibrium.- 4.3 Atmospheric Models.- 4.3.1 Limb Darkening.- 4.3.2 Model Calculations in LTE.- 4.3.3 Models with Departures from LTE.- 4.4 The Chemical Composition of the Sun.- 4.4.1 Spectrum Synthesis.- 4.4.2 The Light Elements Lithium, Beryllium, and Boron.- 4.4.3 Helium.- 4.5 Bibliographical Notes.- 5. Oscillations.- 5.1 Observations.- 5.1.1 Five-Minute Oscillations.- 5.1.2 The Spectrum of Solar Oscillations.- 5.1.3 Low-Degree p Modes.- 5.1.4 Line Width and Line Asymmetry.- 5.2 Linear Adiabatic Oscillations of a Non-Rotating Sun.- 5.2.1 Basic Equations.- 5.2.2 Spherical Harmonic Representation.- 5.2.3 The Cowling Approximation.- 5.2.4 Local Treatment.- 5.2.5 Boundary Conditions.- 5.2.6 Asymptotic Results.- 5.3 Helioseismology.- 5.3.1 Direct Modeling and Inversion.- 5.3.2 Speed of Sound in the Solar Interior.- 5.3.3 Depth of the Convection Zone.- 5.3.4 Chemical Constitution.- 5.3.5 Equation of State.- 5.3.6 Internal Mixing.- 5.3.7 Precise Determination of the Solar Radius.- 5.3.8 Internal Rotation.- 5.3.9 Travel Time and Acoustic Imaging.- 5.4 Excitation and Damping.- 5.4.1 The ? Mechanism.- 5.4.2 Stochastic Excitation by Convection.- 5.5 Bibliographical Notes.- 6. Convection.- 6.1 Stability.- 6.2 Mixing-Length Theory.- 6.2.1 The Local Formalism.- 6.2.2 Numerical Test Calculations.- 6.2.3 Overshooting: A Non-local Formalism.- 6.3 Granulation.- 6.3.1 The Observed Pattern.- 6.3.2 Models.- 6.3.3 Mean Line Profiles.- 6.4 Mesogranulation.- 6.5 Supergranulation.- 6.5.1 The Velocity Field and the Network.- 6.5.2 Convective Nature.- 6.5.3 The Effect of Rotation.- 6.6 Giant Cells.- 6.6.1 Tracer Results.- 6.6.2 Spectroscopic Results.- 6.7 Bibliographical Notes.- 7. Rotation.- 7.1 Axis of Rotation.- 7.2 Oblateness.- 7.2.1 Origin.- 7.2.2 Measurements.- 7.3 Rotational History.- 7.3.1 The Initial State.- 7.3.2 Torques.- 7.3.3 Evolution of the Solar Rotation.- 7.4 The Angular Velocity of the Sun.- 7.4.1 The Internal Angular Velocity.- 7.4.2 The Angular Velocity at the Surface.- 7.4.3 Meridional Circulation.- 7.4.4 Correlation of Flow Components.- 7.5 Models of a Rotating Convection Zone.- 7.5.1 Conservation of Angular Momentum.- 7.5.2 Mean-Field Models.- 7.5.3 Explicit Models.- 7.6 Bibliographical Notes.- 8. Magnetism.- 8.1 Fields and Conducting Matter.- 8.1.1 The Induction Equation.- 8.1.2 Electrical Conductivity on the Sun.- 8.1.3 Frozen Magnetic Field.- 8.1.4 The Magnetic Force.- 8.2 Flux Tubes.- 8.2.1 Concentration of Magnetic Flux.- 8.2.2 Observational Evidence for Flux Tubes.- 8.2.3 Vertical Thin Flux Tubes.- 8.2.4 Curved Thin Flux Tubes.- 8.2.5 Thermal Structure of Photospheric Tubes.- 8.3 Sunspots.- 8.3.1 Evolution and Classification.- 8.3.2 Sunspot Models.- 8.3.3 Sunspots and the "Solar Constant".- 8.3.4 Dots and Grains.- 8.3.5 Oscillations in Sunspots.- 8.3.6 The Evershed Effect.- 8.4 The Solar Cycle.- 8.4.1 Global Magnetism.- 8.4.2 Mean-Field Electrodynamics.- 8.4.3 The Kinematic ?? Dynamo.- 8.4.4 The Magnetohydrodynamic Solar Dynamo.- 8.5 Bibliographical Notes.- 9. Chromosphere, Corona, and Solar Wind.- 9.1 Empirical Facts.- 9.1.1 The Chromosphere.- 9.1.2 The Transition Region.- 9.1.3 The Corona.- 9.1.4 The Wind.- 9.2 Consequences of High Temperature.- 9.2.1 Heat Conduction.- 9.2.2 Expansion.- 9.3 The Magnetic Field in the Outer Atmosphere.- 9.3.1 Magnetic Field Measurements.- 9.3.2 Potential Field Extrapolation.- 9.3.3 The Force-Free Field.- 9.3.4 Prominences.- 9.3.5 Magnetic Braking of Solar Rotation.- 9.4 The Energy Balance.- 9.4.1 Needs.- 9.4.2 Heating.- 9.5 Explosive Events.- 9.5.1 Flares and Other Eruptions.- 9.5.2 Release of Magnetic Energy.- 9.6 Bibliographical Notes.- List of Symbols.- References.