Journal article
Quasilinear Model of Jovian Whistler Mode Emission
Journal of geophysical research. Space physics, Vol.126(12), e2021JA029930
12/2021
DOI: 10.1029/2021JA029930
Abstract
The whistler mode chorus emissions are pervasively detected by the Juno satellite in Jupiter’s magnetospheric environment. This article pays particular attention to a sample observation made by the Juno on 3 November 2019, where typical whistler mode chorus waves are measured. The emission is characterized by a broad range of wave frequencies from below fce/2, where fce denotes the local electron cyclotron frequency, down to the lower‐hybrid frequency, with a gradually downshifting frequency over time. The excitation appears to coincide with the detection of a “butterfly” pitch‐angle distribution and the expected loss‐cone feature associated with the energetic electrons. These anisotropic features, especially the butterfly pitch‐angle distribution, gradually disappear as the waves are excited and the electron phase space distribution becomes isotropic. The aim of this article is to model the characteristics by means of quasilinear kinetic theory of the whistler instability driven by a loss‐cone electron distribution function with a narrow loss‐cone angle, which is to be expected from low‐latitude regions of the Jovian magnetosphere. It is shown that the theoretically constructed dynamic wave spectrum is consistent with the observation made on 3 November 2019. The present finding demonstrates that the quasilinear theory can be a powerful theoretical tool for interpreting various Jovian plasma wave emissions, which includes the whistler waves, but also other wave modes.
Plain Language Summary
NASA’s Juno space probe orbiting the planet Jupiter since 2016, has detected the whistler waves. It is the same type of very low frequency electromagnetic waves generated by lightning in the Earth’s atmosphere, which can be converted to whistling audio wave using a suitable receiver. This article puts forth a plasma physics based explanation of the Juno whistler wave observation. According to this theory, the spiraling motion of energetic electrons trapped in Jupiter’s magnetic dipole field collectively amplify the very low frequency electromagnetic noise‐like signals in a manner analogous to the process taking place in the Earth’s upper atmosphere.
Key Points
Quasilinear model of whistler instability excited by the loss‐cone electron distribution is formulated
The theoretical result compares reasonably well against Juno observation
This shows that the quasilinear theory is a useful tool for interpreting Jovian plasma wave emissions and radiations
Details
- Title: Subtitle
- Quasilinear Model of Jovian Whistler Mode Emission
- Creators
- P. H. Yoon - University of Maryland, College ParkJ. D. Menietti - University of IowaW. S. Kurth - University of IowaF. Allegrini - The University of Texas at San AntonioS. J. Bolton - Southwest Research Institute
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.126(12), e2021JA029930
- DOI
- 10.1029/2021JA029930
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 17
- Grant note
- NASA, Science Mission Directorate (SMD) (New Frontiers Program) NASA (NNH18ZDA001N‐HSR; 80NSSC19K1262; 699041X) NSF (1842643)
- Language
- English
- Date published
- 12/2021
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455551002771
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