The Solar spectrum : proceedings of the symposium held at the University of Utrecht, 26-31 August, 1963

A good deal of our information on solar physics and on solar phenomena is derived from the solar spectrum. A quantitative interpretation of this spectrum was only possible after 1920, after the establishment of Bohr's atomic model, the discovery of Saha's law, and the development of spectrophotometry. The resolving and light gathering powers of our instruments have greatly increased since. We have seen an enormous progress in our theoretical under­ standing of basic atomic phenomena, and of the intricate problems concerned with the transfer of energy through a complicated structure like the sun's outer layers. In particular the observable part of the solar spectrum tremen­ dously enlarged since the introduction, in the years after 1945, of radio­ astronomy, enabling us to study the solar spectrum between wavelengths of some mm to about 15 m, of space research, giving access to the whole electro­ magnetic spectrum below 3000 A, down to about 0. 01 A. Further, the low and high energetic components of the solar particles spectrum have been dis­ covered with space probes (the solar wind), rockets, balloons (the so-called sub­ cosmic-ray particles) and cosmic ray monitors (solar cosmic ray bursts). The extreme wealth of this spectrum, much vaster in extent than the earlier investigators could only dream of, is an important source of information. It looked appropriate to us, after the rapid development of this branch of science,' to invite the world's leading solar physicists to Utrecht for a summa­ rizing symposium on the whole solar spectrum. Front Matter....Pages I-XIV Opening Address....Pages 1-2 Fourty Years of Solar Spectroscopy....Pages 3-25 Front Matter....Pages 27-27 La Structure De La Photosphere....Pages 29-88 The Current Revision of the Solar Spectrum Table λ 2935 Å to λ 8770 Å....Pages 89-101 Discussion on Line Formation and Photospheric Structure....Pages 102-109 Discussion on New Instrumental Techniques....Pages 110-115 Discussion on Photospheric Motions....Pages 116-127 Front Matter....Pages 129-129 The Theory of the Chromospheric Spectrum....Pages 131-150 The Chromospheric Spectrum at Eclipse....Pages 151-178 Rocket Spectra of the Chromosphere....Pages 179-205 Discussion on the Quiet Chromosphere....Pages 206-218 Front Matter....Pages 219-219 Spectra of Solar Activity Regions....Pages 221-239 About the Flare Problem....Pages 240-248 Discussion on the Active Chromosphere....Pages 249-270 Front Matter....Pages 271-271 The Theory of the Coronal Spectrum....Pages 273-279 The Coronal Spectrum....Pages 280-292 Discussion on the Corona....Pages 293-310 Front Matter....Pages 311-311 Particle and Radio Emission from the Sun....Pages 313-341 The Variable Solar Radio Spectrum....Pages 342-397 Non-Thermal Sources and Amplified Emission in Solar Radio Bursts....Pages 398-407 Front Matter....Pages 311-311 Some Aspects of Type-IV Continuum Radiation on Decimeter Wavelengths....Pages 408-412 Discussion on Radio and Particle Emission from the Sun....Pages 413-417