Formation of electron radiation belts at Saturn by Z-mode wave acceleration
- At Saturn electrons are trapped in the planet's magnetic field and accelerated to relativistic energies to form the radiation belts, but how this dramatic increase in electron energy occurs is still unknown. Until now the mechanism of radial diffusion has been assumed but we show here that in-situ acceleration through wave particle interactions, which initial studies dismissed as ineffectual at Saturn, is in fact a vital part of the energetic particle dynamics there. We present evidence from numerical simulations based on Cassini spacecraft data that a particular plasma wave, known as Z-mode, accelerates electrons to MeV energies inside 4 R-S (1 R-S = 60,330 km) through a Doppler shifted cyclotron resonant interaction. Our results show that the Z-mode waves observed are not oblique as previously assumed and are much better accelerators than O-mode waves, resulting in an electron energy spectrum that closely approaches observed values without any transport effects included.
Author details: | Emma E. WoodfieldORCiD, Richard B. HorneORCiD, Sarah A. GlauertORCiD, John D. MeniettiORCiD, Yuri ShpritsORCiDGND, William S. KurthORCiD |
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URN: | urn:nbn:de:kobv:517-opus4-468342 |
DOI: | https://doi.org/10.25932/publishup-46834 |
ISSN: | 1866-8372 |
Title of parent work (German): | Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe |
Publication series (Volume number): | Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe (1032) |
Publication type: | Postprint |
Language: | English |
Date of first publication: | 2020/12/14 |
Publication year: | 2018 |
Publishing institution: | Universität Potsdam |
Release date: | 2020/12/14 |
Tag: | astrophysical plasmas; diffusion; giant planets; magnetospheric physics; pitch angle; plasma; radio; region |
Issue: | 1032 |
Number of pages: | 9 |
Source: | Nature Communications 9 (2018) 5062 DOI: 10.1038/s41467-018-07549-4 |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 50 Naturwissenschaften / 500 Naturwissenschaften und Mathematik |
Peer review: | Referiert |
Publishing method: | Open Access / Green Open-Access |
License (German): | CC-BY - Namensnennung 4.0 International |