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Positive ion composition measurements in the D and E regions were performed on three rocket flights during the 1966 solar eclipse program conducted at Cassino, Brazil. The E region results showed that, at totality, NO+ and O2+ decreased in density while the ratio NO+/O2 increased. Long-lived meteoric ions appeared to be unaffected during the short period of the eclipse. A submerged layer of meteoric ions became prominent at totality when the molecular ion densities were smallest and produced a sporadic E layer. The D region results indicated that the decay in the water cluster ions at totality was probably less than a factor of four in the vicinity of 80 km. This work represents part of a continuing Air Force program to study lower ionospheric processes which affect communications. (Author).
Vertical pulse sounding at 30, 60, 180, and 520 kHz at Quabbin Reservoir, MA, USA, reveals diurnal and seasonal variations in structure, reflectivity, and height of the lower ionosphere. A solid state wideband amplifier feeds 10 kW peak power into a ground-laid six-element antenna. A special digital sampling and integration scheme selects median values of amplitude and phase received at perpendicular loop antennas. Day and nighttime D-region model profiles are fitted to the observed data by matching group height and reflection coefficient. Emphasis is placed on the nighttime residual E-layer observed at 100 km with an electron density, under undisturbed conditions, around 1000/cc. Long and short term variability of this layer is considerable. It is often semi-transparent as indicated by simultaneous E- and F-region echoes, suggesting the presence of a valley above the nighttime E-layer. (Author).
"Low Frequency Waves and Turbulence in Magnetized Laboratory Plasmas and in the Ionosphere was developed from courses taught by the author at the universities of Oslo and Tromso in Norway. Suitable for undergraduates, graduate students and researchers, the first part of the book is devoted to discussing some relevant plasma instabilities and the free energy that drives them. In the second part, the more advanced topics of nonlinear models and the interactions of many modes are discussed. Theoretical tools available for turbulence modelling are also outlined. The book summarizes a number of studies of low-frequency plasma waves, drift waves in particular, from laboratory and space experiments."--Prové de l'editor.
Low latitude observations of VLF/LF pulse reflections from the lower ionosphere obtained at nine locations to the east and west of a transmitter in southeastern Brazil are described. The data provide a variety of information on the reflection properties of the ionosphere below about 90 km altitude. Aspects of the data are presented in quasi-dimensional formats useful for identifying ionosphere structure and variability, and detailed analyses of portions of the data provided, which characterize the effective heights of the reflection coefficients of the ionosphere at noon and midnight, over a frequency range from 15 to 65 kHz. Electron density models of the ionosphere, derived from VLF/LF reflection data are also discussed. Keywords: VLF propagation; LF Propagation; Ionosphere reflectivity d region.
Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 87. This volume provides a review of progress made in recent years in experimental and theoretical investigation of the upper mesosphere and lower thermosphere and coupling between these regions and the ionosphere. Detailed study of the mesosphere/lower thermosphere/ionosphere (MLTI) region has historically been difficult because of its relative inaccessibility to direct measurement techniques and the complex and highly coupled processes which occur there. Although we have still not successfully unraveled all these complex interactions, we have made significant recent progress toward a fuller unde...
The earth's ionosphere in the altitude range of 50 to 200 km was investigated by rocket-borne sensors, supplemented by ground-based measurement. The rocket payloads included mass spectrometers, energetic particle detectors, Langmuir probes and radio propagation experiments. Where possible, rocket flights were included in studies of specific phenomena, and the availability of data from other experiments greatly increased the significance of the results. The principal ionospheric phenomena studied were: winter anomaly in radiowave absorption, ozone and molecular oxygen densities, mid-latitude sporadic-E layers, energetic particle precipitation at middle and low latitudes, ionospheric instabilities and turbulence, and solar eclipse effects in the D and E regions. This document lists personnel who worked on the project, and provides a bibliography of resultant publications. Bowhill, Sidney A. Unspecified Center NGR-14-005-181...