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| Titel |
Auroral ion outflow: low altitude energization |
| VerfasserIn |
K. A. Lynch, J. L. Semeter, M. Zettergren, P. Kintner, R. Arnoldy, E. Klatt, J. LaBelle, R. G. Michell, E. A. MacDonald, M. Samara |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 25, no. 9 ; Nr. 25, no. 9 (2007-10-02), S.1967-1977 |
| Datensatznummer |
250015911
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| Publikation (Nr.) |
 copernicus.org/angeo-25-1967-2007.pdf |
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| Zusammenfassung |
| The SIERRA nightside auroral sounding rocket made observations of the origins
of ion upflow, at topside F-region altitudes (below 700 km), comparatively
large topside plasma densities (above 20 000/cc), and low energies (10 eV).
Upflowing ions with bulk velocities up to 2 km/s are seen in conjunction
with the poleward edge of a nightside substorm arc. The upflow is limited
within the poleward edge to a region (a) of northward convection, (b) where
Alfvénic and Pedersen conductivities are well-matched, leading to good
ionospheric transmission of Alfvénic power, and (c) of soft electron
precipitation (below 100 eV). Models of the effect of the soft precipitation
show strong increases in electron temperature, increasing the scale height
and initiating ion upflow. Throughout the entire poleward edge, precipitation
of moderate-energy (100s of eV) protons and oxygen is also observed. This ion
precipitation is interpreted as reflection from a higher-altitude,
time-varying field-aligned potential of upgoing transversely heated ion
conics seeded by the low altitude upflow. |
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