Evidence of energy dependent mechanisms for the precipitation of auroral electrons |
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Authors: | JM Bosqued H Reme |
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Institution: | Centre d''Etude Spatiale des Rayonnements, Université Paul Sabatier, Toulouse, France |
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Abstract: | This paper discusses the experimental results on electron precipitation in a diffuse aurora obtained by a sounding rocket launched from ANDENES (L ~ 6·2) on 3 November 1968. A considerable increase in the intensity of low energy electrons, Ee ? 5 keV, followed a large precipitation of more energetic electrons Ee ? 5 keV. From the observation of angular distributions and an estimate of the diffusion coefficient (Dα ? 10?3 (sec)?2), it is suggested that this higher energy precipitation is induced by gyroresonant interactions of magnetospheric electrons with radiation in the whistler mode. The lower energy precipitation separated in time and/or space, shows quasi-periodic modulations in the 5–15 sec range with periods close to the bounce period. It is suggested that this precipitation is the result of bounce-resonance interactions with electrostatic waves in the equatorial plane. Finally, from a comparison between the experimental energy spectra and plasma sheet spectra it can be concluded that these electrons are injected from the plasma sheet during a substorm and are then diffused and precipitated by energy dependent mechanisms. |
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