Abstract In the 1970's major advances in the understanding of auroral processes were brought about by observations of plasmas and electric fields within the regions of space responsible for auroral particle acceleration. The major contribution of these observations was the verification of the existence of electric fields with components parallel to the magnetic field over large regions of altitude (1000–20000 kilometers). These electric fields constitute potential drops of several kilovolts, accelerating magnetospheric electrons downward to form the aurora and ionospheric ions upward, where they contribute significantly to the magnetospheric hot ion population. Perpendicular spatial scales of ∼100 kilometers are most common, although finer scales have been observed embedded, and individual small amplitude double layers occur on much smaller parallel spatial scales. More recently, these same data sets have revealed the existence of ∼100 V electric potential drops directed downward in return current regions. Downward electric fields are in a direction to accelerate electrons out of the ionosphere and tend to retard the propagation of ions upward. An association between upflowing electron beams and tranversely heated ions at low altitude has been noted, and a causal relationship between downward electric fields and ion conics is suggested.
Potential structures and particle acceleration on auroral field lines
Advances in Space Research ; 4 , 2-3 ; 499-508
1984-01-01
10 pages
Article (Journal)
Electronic Resource
English
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