The Solar Chromosphere and Corona: Quiet Sun

ISBN-13: 9789401017176 / Angielski / Miękka / 2011 / 515 str.

R. G. Athay

Opis

The widespread tendency in solar physics to divide the solar atmosphere into separate layers and to distinguish phenomena of solar activity from phenomena of the quiet Sun emphasizes the wide ranging diversity of physical conditions and events occurring in the solar atmosphere. This diversity spans the range from a neutral, essentially quiescent atmosphere to a highly ionized, violently convective atmosphere; from a domain in which magnetic field effects are unimportant to a domain in which the magnetic pressure exceeds the gas pressure, and from a domain in which the particle motions are Maxwellian to a domain in which an appreciable fraction of the particles is accelerated to relativistic energies. It is now widely recognized that the chromosphere and corona have a common origin in the mechanical energy flux generated in the hydrogen convection zone lying beneath the photosphere. Furthermore, magnetic field phenomena appear to be as vital to the structure of th~ quiet Sun as to the active Sun. For these reasons it appears desirable to present a unified treatment of the entire solar atmosphere, both active and quiet, in a single volume. On the other hand, such a treatise must be very long if it is to avoid being superficial, and it is very difficult for a single author to write authoritatively on such a wide range of topics.

Spis treści

I. Introduction.- 1. Chromospheres and Coronas.- 2. Goals for Solar Physics.- 3. Chromosphere and Coronal Boundaries.- 4. Methods of Observation.- 5. The K- and F-Coronas.- 6. Comments on Discrete Geometrical Features.- 7. Depths of Line Formation.- II. Structural Features.- 1. Observational Methods.- 2. The Photospheric Structure.- 3. Chromospheric Network.- 4. Chromospheric Fine Structure on the Disk.- 5. Spicule Structure.- 6. Transition Region Structure.- 7. Non-Spherical Modeling.- 8. Chromospheric Active Region Structure.- 9. Observations of Coronal Structures.- 10. Fine Structure of Inner Corona.- 11. Coronal Streamers.- 12. Coronal Rays and Plumes.- 13. Coronal Disk Structures and Coronal Holes.- 14. Prominences.- 15. Solar Cycle Effects.- III. Macroscopic Motions.- 1. Measuring Systematic Motions.- 2. Photospheric Motions.- A. Wave Frequency.- B. Phase Relations.- C. Velocity Amplitude and Cell Size.- D. Discussion.- 3. Chromospheric Motions.- A. Spicules and Fibrils.- B. Cell Bright Points.- C. Chromospheric Oscillations.- D. Doppler Broadening of Chromospheric Lines.- 4. Small Scale Coronal Motions.- 5. Coronal Expansion: The Solar Wind.- 6. Prominence Motions.- 7. Impulsive Motions.- 8. Mass Balance and Energy Transport in Mass Flow.- IV. Magnetic Fields.- 1. Method of Observation.- 2. Energy Considerations.- 3. Polar Fields and UM Regions.- 4. Evolution of Large Scale Fields.- 5. Structure and Evolution of Small Scale Fields.- 6. Coronal Magnetic Fields.- V. Spectral Characteristics.- 1. Visual and Near Infrared Disk.- 2. Visual and Near Infrared Limb.- A. Chromospheric Eclipse Data.- B. Chromospheric Limb Outside of Eclipse.- C. Coronal Eclipse Data.- D. Coronal Limb Data Outside of Eclipse.- 3. Infrared, Radio and XUV Continuum Data.- A. Infrared and Radio Data.- B. XUV Data.- 4. XUV Emission Lines.- VI. Analytical Methods for Spectroscopic Data.- 1. Scattering Continuum.- A. Electron Scattering.- B. Rayleigh Scattering.- 2. Bound-Free Continua: Effectively Thin Case.- A. H-.- B. Balmer and Paschen Bound-Free Continua.- C. Helium Bound-Free Continua.- 3. Free-Free Continua.- 4. Total Line Intensities: Effectively Thin Case.- A. Two-Level Atom.- B. Three-Level Atom.- 5. Profiles of lines and Bound-Free Continua: Effectively Thick Case.- A. A Form of the Line Transfer Equation for Non-Coherent Scattering.- B. Solution of the Pseudo Line Transfer Equation.- C. The Influence of a Chromosphere.- D. Multilevel Effects.- E. Lines Formed by Coherent Scattering and Bound-Free Continua.- VII. Empirical Chromospheric and Coronal Models.- 1. Summary Models.- 2. Conditions at the Optical Limb.- 3. The Temperature Minimum Region.- A. Radiation Losses.- B. Empirical Determination of Tmin.- 4. The Low Chromosphere.- 5. The Middle Chromosphere.- A. General Comments.- B. Visual Continuum.- C. Lyman Continuum.- D. Spectral Lines on the Disk.- E. Helium lines.- 6. The High Chromosphere.- A. Mean Spherically Symmetric Model.- B. Spicule Models.- C. Spectral Line Intensities.- 7. The Chromosphere-Corona Transition Region.- 8. The Corona.- A. Density Models.- B. Ionization Temperature.- C. Line Width Temperatures.- D. Line Intensity Ratios.- E. Radio Temperatures.- F. Temperature Distribution.- VIII. Chromospheric Structure Inferred from Spectral Lines.- 1. Chromospheres and Coronas as Phenomena of Stellar Atmospheres.- 2. Influence of the Chromospheric Temperature Rise.- 3. Influence of the Chromospheric Increase in Doppler Width.- 4. Ca ii lines.- 5. Mg ii Lines.- 6. Neutral Metal Lines.- 7. Hydrogen Lines.- 8. C ii and O i Lines.- 9. Summary.- IX. Energy and Momentum Balance.- 1. Energy Balance.- 2. Radiation Loss Rates.- 3. Thermal Stability.- 4. Coronal Energy Loss by Thermal Conduction and Evaporation.- 5. Energy Balance Within the Transition Region.- 6. The Base of the Transition Region.- 7. The Effect of Motions.- 8. Energy Losses from the Chromosphere.- A. Upper Chromosphere.- B. Middle Chromosphere.- C. Low Chromosphere and Tmin Region.- 9. The Quiet Sun Solar Wind.- A. An Inconsistency of Hydrostatic Equilibrium.- B. Isothermal and Polytropic Expansion.- C. Expansion Combined with Thermal Conduction.- D. Two-Fluid Models.- E. Evaporative Models.- F. The Observational Solar Wind.- 10. Spicule Mechanisms.- A. Summary of Spicule Characteristics.- B. Summary of Theoretical Models.- C. Shock Wave Models.- D. Jets Driven by Gas Pressure.- E. Jets Driven by a Combination of Gas Pressure and Hydrodynamic Forces.- F. Jets Driven by Radiation Pressure.- G. Magnetically Driven Spicules.- X. Wave Generation and Heating.- 1. Wave Generation.- A. Expected Wave Modes.- B. Wave Equations.- C. Acoustic-Gravity Waves.- D. Magneto-Acoustic Waves.- E. Magneto-Acoustic-Gravity Waves.- 2. Interpretation of 5 Minute Oscillations.- A. Location of Waves in ki, ?1 Plane.- B. Models for 5 Minute Oscillations.- 3. Generation of Waves by the Convection Zone.- A. Convective Overshoot.- B. Overstability.- C. Convective Compression.- 4. Heating.- A. Chromospheric Models.- B. Transition Region and Coronal Models.- 5. Acoustic Production of Stellar Chromospheres and Coronas.