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Cluster observations of energetic ionospheric ion beams in the auroral region: Acceleration and associated energy-dispersed precipitation

Bosqued, JM; Ashour-Abdalla, M; Marchaudon, A; Laakso, H; Umeda, T; ElAlaoui, M; Peroomian, W; ... Fazakerley, A; + view all (2006) Cluster observations of energetic ionospheric ion beams in the auroral region: Acceleration and associated energy-dispersed precipitation. Geophysical Research Letters , 33 (12) , Article L12102. 10.1029/2006GL025708. Green open access

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Abstract

This paper presents a detailed study of the Feb. 14, 2001 Cluster northern auroral pass at mid-altitudes ( 4 - 5 RE), characterized by observations of a series of energy-dispersed ion structures in a region of poleward convection. In contradiction with one current view, that ions populating these energy-dispersed signatures originate sporadically in the magnetotail, Cluster directly observed energetic (0.2 - 15 keV), field-aligned H(+) ions of ionospheric origin. The ions were ejected at the top of a steady auroral acceleration region near 72.5 degrees ILAT, then bounced on closed field-lines, and were finally dispersed poleward in latitude by the E x B drift effect. Simple but realistic latitudinal drift computations demonstrate that the anticipated location of successive bouncing echoes coincides rather well with the Cluster observations. Best agreement is reached when the particles are further accelerated ( presumably nonadiabatically) by 1 - 2 keV, as they periodically cross the tail neutral sheet.

Type: Article
Title: Cluster observations of energetic ionospheric ion beams in the auroral region: Acceleration and associated energy-dispersed precipitation
Open access status: An open access version is available from UCL Discovery
DOI: 10.1029/2006GL025708
Publisher version: http://dx.doi.org/10.1029/2006GL025708
Language: English
Additional information: Copyright 2006 by the American Geophysical Union
Keywords: Earths magnetosphere, Electron, Field, Oval, CIS
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics
URI: https://discovery.ucl.ac.uk/id/eprint/162629
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