Nighttime F-region plasma structures observed by rocket-borne Langmuir and high frecuency capacitance probes from Natal, Brazil

Abstract

Simultaneous in-situ measurements of electron densities were made by rocket-borne Langmuir and High Frequency Capacitance probes from the equatorial station Natal in Brazil, using Brazilian SONDA ill rockets. On both occasions, the rockets, carrying a swept voltage Langmuir probe and a dual frequency High Frequency Capacitance probe, in addition to other experiments, were launched into the nighttime ionosphere. During the first launch the rocket passed through developing plasma bubbles and during the second launch it passed through a practically bubbleless F-region. Electron density irregularities of vertical scale sizes ranging from a few kilometers to as large as 40 to 50 kilometers were observed by both probes. The general features of the large scale structures as observed by the two probes were similar, but there existed also considerable differences. For instance, the amplitudes of small scale structures in the F-region as observed at one of the HFC frequencies were generally larger than those measured by the LP. Experimental factors as well as physical processes responsible for these differences are discussed.