Width-amplitude variations of electron acoustic solitary waves in auroral plasma

The presence of dynamic, large amplitude solitary waves in the auroral regions of space is well known. They consist of both electron acoustic and ion acoustic solitary structures. A previous analysis of fully nonlinear ion acoustic solitary waves has shown a characteristic width-amplitude variation pattern which is found to be consistent with the recent POLAR spacecraft observations. The analysis is extended to study fully nonlinear electron acoustic solitary waves in a magnetized plasma in the presence of beam electrons. It is found that the presence of a hot electron beam is crucial for the excitation of positive amplitude electron acoustic solitary waves (electron acoustic holes). It is also found that with changing bulk electron temperature, the width increases with increasing amplitude while for a changing wave velocity, the width decreases.