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| Titel |
A new diffusion model for plasmaspheric hiss and lightning-generated whistlers and its effect on radiation belt dynamics |
| VerfasserIn |
Sarah Glauert, Richard Horne, Nigel Meredith |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250081894
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| Zusammenfassung |
| The flux of relativistic electrons in the Earth's radiation belts is highly variable and can change by orders of magnitude on timescales of a few hours. Understanding the drivers for these changes is important as energetic electrons can damage satellites. Several models of the high-energy electron population now exist where the electron phase-space density is modelled using a 3-D Fokker-Planck equation incorporating the effects of radial transport, wave-particle interactions and collisions. Wave-particle interactions are incorporated into the models as pitch-angle and energy diffusion coefficients. Here we present results from the BAS radiation belt model, using new diffusion coefficients for plasmaspheric hiss and lightning-generated whistlers which are calculated using a representation of the wave power that decreases as the resonance cone is approached. The new diffusion coefficients are derived using the BAS wave database and are functions of L shell, energy, pitch-angle and geo-magnetic activity. Several wave-normal angle models are considered including one where the peak wave-normal angle varies with latitude. Our results show that radiation belt dynamics are reproduced better when the AE index, rather than Kp, is used to drive the wave-particle interactions and that the model best reproduces the observed data when the wave-normal angle distribution has a peak that varies with latitude and a wide angular spread. We show a comparison between the model and CRRES data for selected events. |
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