Journal article
The Role of Intense Upper Hybrid Resonance Emissions in the Generation of Saturn Narrowband Emission
Journal of geophysical research. Space physics, Vol.124(7), pp.5709-5718
07/2019
DOI: 10.1029/2019JA026855
Abstract
Twenty high‐inclination ring‐grazing orbits occurred in the final period of the Cassini mission. These orbits intercepted a region of intense Z‐mode and narrowband (NB) emission (Ye et al., 2010, https://doi.org/10.1029/2009JA015167) along with isolated, intense upper hybrid resonance (UHR) emissions that are often associated with NB source regions. We have singled out such UHR emission seen on earlier Cassini orbits that also lie near the region crossed by the ring‐grazing orbits. These previous orbits are important because Cassini electron phase‐space distributions are available and dispersion analysis can be performed to better understand the free energy source and instability of the UHR emission. We present an example of UHR emission on a previous orbit that is similar to that observed during the ring‐grazing orbits. Analysis of the observed plasma distribution of the previous orbit leads us to conclude that episodes of UHR emission and NB radiation observed during the ring‐grazing orbits are likely due to plasma distributions containing loss cones, temperature anisotropies, and strong density gradients near the ring plane. Z‐mode emissions associated with UHR and NB emission can be in Landau resonance with electrons to produce scattering or acceleration (Woodfield et al., 2018, https://doi.org/10.1038/s41467‐018‐07549‐4).
Key Points
Upper hybrid resonances (UHR) occur at Saturn near the magnetic equator on high‐inclination inner magnetospheric orbits
These regions can be sources of Z‐mode and narrowband (NB) emission
Observed electron plasma distribution contains a weak loss cone unstable to Z‐ and O‐mode wave growth.
Details
- Title: Subtitle
- The Role of Intense Upper Hybrid Resonance Emissions in the Generation of Saturn Narrowband Emission
- Creators
- J. D. Menietti - University of IowaP. H. Yoon - Korea Astronomy and Space Science InstituteD. Pisa - CAST. F. Averkamp - University of IowaA. H. Sulaiman - University of IowaW. S. Kurth - University of IowaO. Santolík - Charles UniversityC. S. Arridge - Lancaster University
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.124(7), pp.5709-5718
- DOI
- 10.1029/2019JA026855
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 10
- Grant note
- National Research Foundation (NRF) (BK21 plus program) JPL (14150) Czech Science Foundation (GACR) (17‐08772S) Czech Academy of Sciences GFT Charity NASA (NNX16AI47G) National Research Foundation (NRF)
- Language
- English
- Date published
- 07/2019
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455542202771
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