Ion composition measurements in the lower ionosphere during the November 1966 and March 1970 solar eclipses
Document ID: 8
Narcisi, R. S.
Bailey, A. D.
Wodyka, L. E.
Philbrick, C. Russell
USAF, Cambridge Research Laboratories, Hanscom AFB, Bedford, MA, U.S.A.
Abstract
Positive ion composition measurements in the D- and lower E-regions were performed on three rocket flights during the November 1966 solar eclipse program conducted at Cassino, Brazil. Progressing into totality, the E-region results showed that NO+ and O2+ decreased in concentration while the ratio NO+/O2+ increased. Long-lived meteoric atomic-ions appeared to be unaffected within the short period of the eclipse. A meteoric ion layer that was submerged prior to totality, became prominent as the molecular ions decayed and produced a sporadic E-layer at 105 km near totality. The D-region results provided evidence for the existence of a fast process for the conversion of NO+ to water cluster ions. The decrease in water cluster ion concentration at totality was probably less than a factor of four in the vicinity of 80 km. Negative ion composition measurements were obtained over Wallops Island, Virginia between 70 and 111 km close to totality of the 7 March 1970 solar eclipse. Heavy negative cluster ions were predominant below 92 km and were restricted to below this altitude, Between 90 and 98 km, and only on rocket descent, there were relatively large concentrations of ions with masses near 16, 32, 46 and 62 amu, probably O-, O2-, NO2- and NO3-. Such large concentrations were not measured in earlier flights in the undisturbed ionosphere and cannot be explained with presently known processes.
Keywords: ion composition, D-region, solar eclipse