Morphology of the southern radio auroral zone

Radar auroral echo characteristics as seen by a 398-MHz phased array radar operated at Homer, Alaska

“…These maps are classified into types that are extensions of the 'diffuse' and 'discrete' echo types introduced by Leadabrand et al (1959) and Presnell et al (1959) for narrow beam radars. Many useful statistical studies have been made showing the diurnal and seasonal dependence of auroral echo characteristics [e.g., Unwin, 1959Unwin, , 1966Leonard, 1962; Blevis et al, 1963;Shipstone, 1969]. We show that interpretation of the occurrence of auroral echoes in terms of control by an electric field and by electron density in the radar scattering volume produces a consistent morphology of the radar aurora in relation to the other observed auroral processes.…”

“…If this is the case, a driving force, such as an electric field, would be required in addition to the presence of significant ionization. Many useful statistical studies have been made showing the diurnal and seasonal dependence of auroral echo characteristics [e.g., Unwin, 1959Unwin, , 1966Leonard, 1962; Blevis et al, 1963;Shipstone, 1969]. Many useful statistical studies have been made showing the diurnal and seasonal dependence of auroral echo characteristics [e.g., Unwin, 1959Unwin, , 1966Leonard, 1962; Blevis et al, 1963;Shipstone, 1969].…”