Multipoint observations of substorm intensifications: The high-latitude aurora and electron injections in the inner equatorial plasma sheet


In recent years, focus in substorm research has been directed to high speed jets of plasma traveling earthward in the magnetotail, called bursty bulk flows (BBFs) and a search for their ionospheric signature(s). One candidate ionospheric signature consists of episodic brightenings of the poleward branch of the aurora and associated forms propagating from the higher to the lower branch. This study extends previous efforts by employing ground-based, optical observations of the high-latitude (70°–80° magnetic latitude) aurora at high spatial and temporal resolution, and supplementing these by equatorial, near-Earth (6 RE) particle measurements during a strong substorm. We describe the brightening and equatorward motion of the high latitude aurora and relate it in time and space to electron injections in the 5–20 keV range earthward of geostationary heights (6 events in 20 min). These observations are placed in the context of the observed 3-phase poleward expansion of the aurora, and the corresponding magnetotail dynamics during the strong substorm under study.

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JGR: Space Physics



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