Correlation analysis of radio-auroral scatter signals

Abstract

Very high frequency radio-auroral scatter signals are regularly observed on an Ottawa–London (Ontario) backscatter circuit operating at 40.35 MHz. For three of these events the scale size and drift velocity of the scattered field at the receiving site were determined by a correlation analysis of the signals received at spaced antennas. The overall east–west extent of the scattering regions was determined from the scale-size measurements. At least two types of event were observed. One type results from scattering by extended regions with horizontal dimensions greater than 200 km and having minimum drift velocities of a few hundred m/s. The second type of event results from simultaneous scattering by a number of independent regions, each having its own drift speed and direction. These regions have drift velocities in excess of 1 km/s and horizontal dimensions often less than 30 km.