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| Titel |
Article: Heating of beam ions by ion acoustic waves |
| VerfasserIn |
A. Vaivads, K. Rönnmark, T. Oscarsson, M. André |
| 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 ; 16, no. 4 ; Nr. 16, no. 4, S.403-412 |
| Datensatznummer |
250013242
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| Publikation (Nr.) |
 copernicus.org/angeo-16-403-1998.pdf |
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| Zusammenfassung |
Satellite measurements show that ion beams
above the auroral acceleration region are heated to hundreds of eV in a
direction perpendicular to the magnetic field. We show that ion acoustic waves
may be responsible for much of this heating. Even in the absence of a positive
slope in the velocity distribution of the beam ions, ion acoustic waves can be
generated by a fan instability. We present analytical estimates of the wave
growth rate and ion beam heating rate. These estimates, which are confirmed by
particle simulations, indicate that the perpendicular temperature of the beam
ions will increase by 30 eV/s, or by 1 eV in 20–25 km. From the simulations we
also conclude that the heating saturates at a perpendicular temperature around
200 eV, which is consistent with observations.
Key words. Ionosphere (wave-particle interactions) ·
Magnetospheric Physics (plasma waves and instabilities) · Space plasma physics
(wave-particle interactions). |
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