Ion acoustic double layers and solitons in auroral plasma

Abstract

Small amplitude ion acoustic double layers and solitons were studied in an auroral plasma consisting of hot and cold electrons and two cold ion species (e.g. oxygen-hydrogen). For the auroral plasma parameters, the analysis predicts either rarefactive double layers or rarefactive solitons or compressive solitons existing in distinct parametric space (N H, T H T C ) , where N H is a relative density of hot electrons and T H, C represents the temperature of hot (cold) electron population. An increase in the oxygen number density reduces the parametric region of rarefactive double layers and at the same time pushes it towards the higher N H values. Both the width (half width) of the double layer (solitons) and their velocities as predicted by the theory, assuming relative oxygen density of 0.2–0.8, are in good agreement with the observed values from the S3-3 and the Viking satellite data.