Rapid electron acceleration in low density regions of Saturn's radiation belt by whistler mode chorus waves

Woodfield, E.E. ORCID: https://orcid.org/0000-0002-0531-8814; Glauert, S.A. ORCID: https://orcid.org/0000-0003-0149-8608; Menietti, J.D.; Averkamp, T.F.; Horne, R.B. ORCID: https://orcid.org/0000-0002-0412-6407; Shprits, Y.Y. 2019 Rapid electron acceleration in low density regions of Saturn's radiation belt by whistler mode chorus waves. Geophysical Research Letters, 46. 7191- 7198. https://doi.org/10.1029/2019GL083071

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Abstract/Summary

Electron acceleration at Saturn due to whistler mode chorus waves has previously been assumed to be ineffective; new data closer to the planet shows it can be very rapid (factor of 104 flux increase at 1 MeV in 10 days compared to factor of 2). A full survey of chorus waves at Saturn is combined with an improved plasma density model to show that where the plasma frequency falls below the gyrofrequency additional strong resonances are observed favoring electron acceleration. This results in strong chorus acceleration between approximately 2.5 RS and 5.5 RS outside which adiabatic transport may dominate. Strong pitch angle dependence results in butterfly pitch angle distributions that flatten over a few days at 100s keV, tens of days at MeV energies which may explain observations of butterfly distributions of MeV electrons near L=3. Including cross terms in the simulations increases the tendency towards butterfly distributions.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1029/2019GL083071
ISSN:	0094-8276
Additional Keywords:	Saturn, Radiation Belt, electron, wave‐particle interaction, whistler mode chorus waves
Date made live:	27 Jun 2019 10:42 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/523962

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1029/2019GL083071

ISSN:

0094-8276

Additional Keywords:

Saturn, Radiation Belt, electron, wave‐particle interaction, whistler mode chorus waves

Date made live:

27 Jun 2019 10:42 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/523962