High Altitude Atmospheric Investigations. Part II. Development of in-situ Experiments for Measurements in the D-Region of the Ionosphere and Their Results

摘要

Results of A3 absorption, Radio absorption measured from the ground is determined by the integral over the electron density weighted with the collision frequency of the electrons with the ambient neutral gas. The boundaries of the relevant conditions are difficult to establish. Absorption is also affected by properties of the ionosphere, and these properties change with seasons, sun position, and other factors. These multiple effectors make unambiguous interpretation impossible. The report describes attempts to select and describe parameters that might most strongly influence radio wave absorption. Technical details of in-situ experiments to measure wind and electron density are communicated and some results obtained with these instruments are presented. It was found that the ratio between the positive ion current and the electron current measured with the guarding probe experiment is affected by both, the ion composition in the ion sheath and by neutral air temperature. This might explain the ambiguities found when a direct comparison of results obtained with 'Langmuir' probes and wave propagation experiments is attempted. The effect might be used to derive local air temperatures provided that the ion composition of the ion sheath is known and that a quantitative theoretical description can be established. (Author)