Ionospheric Effects During The Partial Solar Eclipse Of July 10 1972

IPSE OF July 10, 1972. Technical rept., Soicher, H. ;Gorman, F.J., Jr;ECOM-4097DA-1-T-061102-B-31-A1-T-061102-B-31-A-01(*ionospheric disturbances, solar eclipses), electron density, atmospheric temperature, polarization, scientific satellitesats-3 satellitePolarization measurements at Fort Monmouth, N.J., using ATS-3 emitted signals and bottomside ionospheric sounding measurements at the subionospheric point were performed during the partial solar eclipse of 10 July 1972. A decrease in the total electron content and the plasma temperature ensued with corresponding diffusive particle fluxes into heights of maximum ionization. The diffusion rate to the height of maximum ionization was comparable to the recombination rate at that altitude. (Author).

A solar eclipse offers a unique opportunity to study the effects of the rapid disappearance and reappearance of solar thermal and ionization radiations on the ionospheric production, loss, and transport processes which affect the total ionospheric number density. Polarization measurements utilizing beacon emissions of the ATS-3 satellite were supplemented with bottomside ionospheric observations made near the subionospheric point during the partial eclipse of 10 Jul 1972. Time variation of the total electron content from 11:00 to 17:30 EST during the eclipse day and during the two days prior to and the three days following it are shown. A comparison of polarization changes during the eclipse day obtained at Fort Monmouth and at Sagamore Hill Radio Observatory, Hamilton, Mass. is given.

Observations of the ionosphere during the 20 July 1963 solar eclipse at Bedford, Massachusetts are presented. A C-4 vertical incidence sounder was used. Critical frequencies and virtual heights of the ionosphere are plotted and compared with a 10-day average curve. Ionograms of the time of first contact, maximum eclipse and fourth contact are included. A series of optical photographs of the sun in eclipse, taken at ground level, are presented. (Author).

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.

Astronomy and Astrophysics Abstracts, which has appeared in semi-annual volumes since 1969, is de voted to the recording, summarizing and indexing of astronomical publications throughout the world. It is prepared under the auspices of the International Astronomical Union (according to a resolution adopted at the 14th General Assembly in 1970). Astronomy and Astrophysics Abstracts aims to present a comprehensive documentation of Iiterature in all fields of astronomy and astrophysics. Every effort will be made to ensure that the average time interval between the date of receipt of the original Iiterature and publication of the abstracts will not exceed eight months. This time interval is near to that achieved by monthly abstracting journals, com pared to which our system of accumulating abstracts for about six months offers the advantage of greater convenience for the user. Valurne 7 contains Iiterature published in 1972 and received before August 15, 1972; some older Iiter ature which was received late and which is not recorded in earlier volumes is also included.