Journal article
Rapid Frequency Variations Within Intense Chorus Wave Packets
Geophysical research letters, Vol.47(15), e2020GL088853
08/16/2020
DOI: 10.1029/2020GL088853
Abstract
Whistler mode chorus waves are responsible for electron acceleration in Earth's radiation belts. It is unclear, however, whether the observed acceleration is still well described by quasi‐linear theory, or if this acceleration is due to intense waves that require nonlinear treatment. Here, we perform a comprehensive statistical analysis of intense lower‐band chorus wave packets to investigate the relationships between wave frequency variations, packet length, and wave amplitude, and their temporal variability. We find that 15% of the wave power is carried by long packets, with low frequency sweep rates (linear trend in time) that agree with the nonlinear theory of chorus wave growth. Eighty‐five percent of the wave power, however, comes from short packets with large frequency variations around the linear trend. The kappa‐like probability distribution of these variations is consistent with random superposition of different waves that could result in a destruction of nonlinear resonant interaction.
Key Points
We investigate the relationships between chorus wave frequency variations, packet length, and wave amplitude
Fifteen percent of the wave power is carried by long packets with low frequency sweep, as predicted by nonlinear chorus wave generation theory
Eighty‐five percent of the wave power comes from packets with large frequency variations that increase as packets become shorter
Details
- Title: Subtitle
- Rapid Frequency Variations Within Intense Chorus Wave Packets
- Creators
- X.‐J. Zhang - University of CaliforniaD. Mourenas - CEA DAM Île-de-FranceA. V. Artemyev - University of California, Los AngelesV. Angelopoulos - University of California, Los AngelesW. S. Kurth - University of IowaC. A. Kletzing - University of IowaG. B. Hospodarsky - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Geophysical research letters, Vol.47(15), e2020GL088853
- DOI
- 10.1029/2020GL088853
- ISSN
- 0094-8276
- eISSN
- 1944-8007
- Number of pages
- 11
- Grant note
- National Science Foundation (NSF) (2026375; 1914594) NASA (921647; NAS5‐01072) National Aeronautics and Space Administration (NASA) (NAS5‐02099) German Aerospace Center (DLR) (50 OC 0302)
- Language
- English
- Date published
- 08/16/2020
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984428797502771
Metrics
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