Ultraviolet and X-ray Spectroscopy of the Solar Atmosphere

by Kenneth J. H. Phillips , Uri Feldman , Enrico Landi

• ISBN13: 9780521841603
• ISBN10: 0521841607
• Format: Hardcover
• Copyright: 2008-08-11
• Publisher: Cambridge University Press

Summary

The solar atmosphere, above the Sun's surface layers, reaches mega-kelvin temperatures and high levels of dynamic activity through processes involving a pervading magnetic field. This book explores one of the principal means of understanding the solar atmosphere, its ultraviolet and soft X-ray emission. The ultraviolet and X-ray spectra of the Sun's atmosphere provide valuable information about its nature - the heat and density of its various parts, its dynamics, and chemical composition. The principles governing spectral line and continuous emission, and how spectral studies lead to deductions about physical properties, are described, together with spacecraft instrumentation from Skylab, SolarMax, Yohkoh, SOHO, TRACE, and Hinode. With introductions to atomic physics and diagnostic techniques used by solar spectroscopists, a list of emission lines in ultraviolet and soft X-ray regions, and a glossary of terms, this is an ideal reference for graduate students and researchers in astrophysics and solar physics.

Table of Contents

Preface	p. ix
The solar atmosphere	p. 1
Introduction	p. 1
Chromosphere, transition region, and corona	p. 2
The ultraviolet and X-ray spectrum of the solar atmosphere	p. 4
Structure of the solar atmosphere	p. 9
Dynamics of the solar atmosphere	p. 14
The active Sun	p. 16
Physical conditions and energy balance	p. 20
Ionization and excitation conditions	p. 24
Chemical composition	p. 27
Solar-type stars	p. 27
Fundamentals of solar radiation	p. 31
Wavelength ranges	p. 31
Specific intensity and flux	p. 32
Radiative transfer and the source function	p. 34
Radiation from the solar atmosphere	p. 35
Radiant intensity and flux	p. 40
Fundamentals of atomic physics	p. 44
Introduction	p. 44
The one-electron atom: Bohr's theory	p. 44
The one-electron atom: quantum theory	p. 48
The multi-electron atom: quantum theory	p. 52
Isoelectronic sequences	p. 61
Interaction between atoms and electromagnetic fields	p. 63
Atomic codes	p. 72
Mechanisms of formation of the solar spectrum	p. 73
Introduction	p. 73
Collisional excitation and de-excitation of atomic levels	p. 73
Level populations	p. 78
Ionization and recombination	p. 83
Ion populations and ionization equilibrium	p. 91
Line radiation	p. 93
Continuum radiation	p. 96
Spectral line profiles	p. 106
Other excitation mechanisms of spectral lines	p. 109
Plasma diagnostic techniques	p. 119
Introduction	p. 119
Electron density diagnostics	p. 119
Electron temperature diagnostics	p. 131
Ion temperature diagnostics	p. 139
Emission measure diagnostics	p. 142
Differential emission measure diagnostics	p. 144
Element abundance diagnostics	p. 150
Ion abundances	p. 155
Plasma dynamics diagnostics	p. 155
Magnetic field diagnostics	p. 161
Spectral codes for solar corona research	p. 162
Ultraviolet and X-ray emission lines	p. 164
Introduction	p. 164
The 1-7 A range	p. 165
The 7-23 A range	p. 166
The 23-170 A range	p. 169
The 170-630 A range	p. 169
The 630-2000 A range (off-limb spectrum)	p. 178
The 630-2000 A range (disk spectrum)	p. 180
Spectrometers and imagers for observing the solar ultraviolet and X-ray spectrum	p. 184
Introduction	p. 184
Transmittance properties of materials	p. 185
Reflectance of VUV, EUV, and X-ray radiation from materials	p. 186
Ultraviolet spectrometers	p. 188
X-ray spectrometers	p. 195
Imaging instruments	p. 200
Instrument calibration	p. 204
Summary of spacecraft instruments	p. 209
Quiet Sun and coronal holes	p. 210
Introduction	p. 210
Quiet Sun corona and coronal holes: structure	p. 211
Quiet Sun corona and coronal holes: plasma properties	p. 214
Quiet Sun transition region	p. 219
Non-thermal broadening of ultraviolet emission lines	p. 221
Quiet Sun dynamic phenomena	p. 224
Coronal waves and oscillations	p. 228
Active regions	p. 231
Introduction	p. 231
Structure of active regions	p. 231
Active region loops	p. 239
Active region densities	p. 245
Active region transient phenomena	p. 247
Solar flares	p. 251
Introduction	p. 251
X-ray flare spectra	p. 251
Ultraviolet flare spectra	p. 256
Flare temperatures and emission measures	p. 258
Flare densities	p. 264
Flare morphology	p. 268
Mass motions in flares	p. 270
Non-thermal electrons	p. 273
X-ray fluorescence lines in flares	p. 273
Ionization equilibrium in flares	p. 275
GOES observations of flares	p. 277
Element abundances	p. 282
Introduction	p. 282
Solar wind abundances	p. 285
Abundances in quiet Sun and coronal hole regions	p. 287
FIP bias in distinct solar structures	p. 290
FIP bias rate of change in the solar atmosphere	p. 291
Is the FIP bias magnitude FIP dependent?	p. 292
Number of free electrons in the photosphere	p. 294
Summary	p. 296
Units	p. 297
Line lists	p. 298
Glossary	p. 328
Further reading	p. 336
References	p. 337
Index	p. 346
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