Solar Eclipses and the Ionosphere

It is a 10ng-standing tradition in this country for any event re1ated to solar activity to enjoy special importance. Because we enjoy the advantage of pro10nged sunny periods, we consider the incidence of some thirty c10udy days each year as a personal af front. I cannot say that we have the facu1ty to produce solar ec1ipses in order to justify an Institute on this subject to be held in Athens, but I can say that the occurrence of a solar ec1ipse over Greece wou1d present, for optica1 and solar astronomers, the highest possibi1ity of exce11ent conditions for observation. We had this opportunity during the May 20, 1966 annu1ar solar ec1ipse over North Africa and southern Europe. At that time we had the p1easure to co11aborate with a 1arge number of research groups of various nationa1ities, who insta11ed optica1 and radio instru ments near or in Lagonissi, which 1ay a10ng the centra1 path, in order to fo110w the ec1ipse. A first meeting was then organized in order to discuss methods of data handling and avai1abi1ity of resu1ts. After a pre1iminary discussion it was suggested that a 1ater meeting shou1d be organized when final resu1ts were avai1ab1e.

Inhalt
Theoretical Aspects.- Ionospheric Effects in Solar Eclipses.- Theoretical Aspects of Solar Eclipses.- The Earth's Exospheric Plasma with Some Comments on Eclipses as a Means of Studying the Ionosphere.- D-Region Chemistry.- The Chemistry of the D-Region.- Mesures d'ozone pendant les eclipses solaires.- Direct Rocket Measurements of the Ionosphere during the Solar Eclipse of November 12, 1966.- Solar Radiation and Layer Theory.- Observations of Solar Ionizing Radiations and Their Significance for the Eclipse-Ionosphere.- X-Ray Emissions from the Sun.- Radio-Astronomical Observations.- Microwave Spectral Observations of Coronal Condensations.- A Survey of Solar Eclipse Measurements in the 130 mm Range.- Distribution of X-Ray Emission from the Sun Deduced from Measurements of Ionospheric Absorption.- Eclipse Studies by Rocket, Satellite, and Partial Reflection Techniques.- D-Region Electron Density Measurements during the Solar Eclipse of May 20, 1966.- Partial Reflection Measurements on the D-Region during the May 20, 1966 Solar Eclipse.- Electron Content Measurements by Beacon S-66 Satellite during the May 20, 1966 Solar Eclipse.- Ionospheric Eclipse Effects.- Recent Ionospheric E and F Region Measurements during Solar Eclipses, and Their Interpretation.- The Annular Solar Eclipse on May 20, 1966 and the Ionosphere.- L'Eclipse de Soleil du 20 Mai 1966.- Quelques Résultats Préliminaires d'Observations Ionosphériques lors de l'Eclipse du Mai 20 1966...- Changes in the Topside Ionosphere during Solar Eclipses.- Concluding Remarks.- Concluding Remarks.- Concluding Statement.