 |
| Titel |
Electron Acceleration at Jupiter: Cyclotron-Resonant Interaction with Whistler-Mode Chorus Waves. |
| VerfasserIn |
Emma Woodfield, Richard Horne, Sarah Glauert, John Menietti, Yuri Shprits |
| Konferenz |
EGU General Assembly 2013
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250081847
|
|
|
|
|
|
| Zusammenfassung |
| It has been shown at the Earth that cyclotron-resonant interactions with whistler-mode waves
are a major contribution to the acceleration of electrons to MeV energies in the
radiation belts. Previous work has suggested that this mechanism is also viable at
Jupiter up to a few MeV outside the orbit of Io. Here we re-examine the data used in
previously published energy diffusion rates for Jupiter for Lshells from 6 to 18
and show that energy diffusion rates should be increased by up to a factor of 8 at
Lshells greater than 10. We investigate the effect of the latitudinal distribution of
chorus waves on the diffusion rates in both energy and pitch angle. We find that
increasing the latitude to which constant power chorus waves extend from ±10° to
±30° increases energy diffusion rates by an order of magnitude or more but also
increases the pitch angle diffusion dramatically such that many more electrons are
scattered into the loss cone and lost. Using a profile of wave power versus latitude
based on Galileo data we find that power increases away from the equator and then
falls off rapidly beyond ±10°. Consequently losses are reduced and much greater
acceleration is predicted. Applying energy and pitch angle diffusion coefficients
based on observed chorus wave power in the British Antarctic Survey Radiation
Belt model we can rapidly increase the electron fluxes from a very soft energy
spectrum to one close to that observed at Jupiter outside the orbit of Io (10 days
for electron energies of approximately 3 MeV) without including radial diffusion. |
|
|
|
|
|