标题：Results of Polar Ionospheric Plasma Observation by the Rocket S-210JA-29 (f. Polar Ionosphere) (Proceedings of the Second Symposium on Coordinated Observations of the Ionosphere and the Magnetosphere in the Polar Regions : Part II)
其他标题：S-210JA-29号機による電離層プラズマの観測結果(f.極域電離層)(第2回極域における電離圏磁気圏総合観測シンポジウム : Part II)
摘要：In order to measure the electron density and density irregularities in the polar ionosphere sounding rocket S-210JA-29 was fired at 19h15m (LT) on July 12, 1977 from Syowa Station, Antarctica. The observational results show that there exists an E_s layer in the altitude region between 85 km and 115 km, and its electron density is 2-4×10^4/cm^3, and the electron density above 115 km is decreasing. The values of the measured electron density profile are rather low compared with the nighttime electron density profiles which were observed until now. The profiles of the electrostatic noise spectrum show remarkable changes against the altitude. The amolitudes of spectrum of the electrostatic noise become great in the region between 95 km and 106 km in the ascending time and between 103 km and 112 km in the descending time. The amplitudes of spectrum have a peak value at 1-2 kHz and the spectrum spreads out to the higher frequency region. Assuming that the observed spectrum of the electrostatic noise to be a natural one, these irregularities seem to be caused partly by a two-stream plasma instability mechanism.
