Radar studies of the aurora
The investigation of the high-latitude aurora by means of the V.H.F. auroral radar SABRE, (Swedish And British auroral Radar Experiment), developed by the Leicester University Ionospheric Physics group, is described. The first two chapters review previous studies of the atmosphere by radar techniques and includes a description of the SABRE radar. The basic radar equation and velocity relationships are derived and the various loss factors examined. From analysis of the echo signal data for the diffuse aurora, and examination of signal data from a radio star, the SABRE radar parameters are established. An investigation is then undertaken of the variation of the electrojet parameters, (derived from application of the radar equation to the SABRE data), with height, electric field strength and geomagnetic conditions. Evidence is found of backscattering from irregularities generated by both two-stream and gradient drift processes. An examination is also made of the echo signals detected at relatively short ranges, of below 370 km, and several causal mechanisms are investigated including scattering processes in the neutral atmosphere. It is evident that aircraft are predominantly the cause of these short-range echoes. This investigation also reveals a number of software and hardware faults in the initial radar configuration. This Thesis is concluded with suggestions for future development of the radar system, which include the implementation of a height-finding facility and improved spectral resolution.