Journal article
Periodic Narrowband Radio Wave Emissions and Inward Plasma Transport at Saturn's Magnetosphere
The Astronomical journal, Vol.159(6), p.249
06/01/2020
DOI: 10.3847/1538-3881/ab818d
Abstract
The abrupt brightening of an Energetic Neutral Atom (ENA) blob or cloud has been interpreted as plasma injection in the Kronian magnetosphere (termed ENA injection herein). Morphologically, there appears to be two types of abrupt ENA cloud brightening: (1) the brightening of a large cloud usually seen at distances >10-12 R-s (R-s similar to 60,268 km) in the midnight or postmidnight region; (2) the brightening of a smaller cloud usually seen at distances R-s around 21-03 magnetic local time. Among many radio waves observed at Saturn, type 2 ENA injections correlate best with the 5 kHz narrowband (NB) waves. Using Cassini Ion and Neutral Camera (INCA) and Radio and Plasma Wave Science (RPWS) data, we examine the periodicities of the type 2 ENA injections and the 5 kHz NB emissions as well as their cross-correlations, which have been previously used to measure the lag times or phase differences. Because correlational analysis can only establish linear relationships, we also use mutual information to establish linear and nonlinear relationships. On average, the peak of the 5 kHz NB emission lags those of the type 2 ENA injection by about a few minutes to 2 hr. The injection of hot plasma to the inner magnetosphere can lead to temperature anisotropy, which can generate electrostatic upper hybrid waves, which upon encountering the high-density gradient at the outer edge of the Enceladus density torus, can mode convert to Z mode and then to O mode. The 5 kHz NB waves commonly propagate in the O mode.
Details
- Title: Subtitle
- Periodic Narrowband Radio Wave Emissions and Inward Plasma Transport at Saturn's Magnetosphere
- Creators
- S. Wing - Johns Hopkins UniversityP. C. Brandt - Johns Hopkins UniversityD. G. Mitchell - Johns Hopkins UniversityJ. R. Johnson - Andrews UniversityW. S. Kurth - University of IowaJ. D. Menietti - University of Iowa
- Resource Type
- Journal article
- Publication Details
- The Astronomical journal, Vol.159(6), p.249
- Publisher
- Iop Publishing Ltd
- DOI
- 10.3847/1538-3881/ab818d
- ISSN
- 0004-6256
- eISSN
- 1538-3881
- Number of pages
- 12
- Grant note
- Andrews University Faculty Research Grant 003; NAS5-97271 / NASA Office of Space Science; National Aeronautics & Space Administration (NASA) NNX12AG81G; NNX15AJ01G; NNX16AQ87G; 80NSSC19K0822; NNX16AQ876; 80NSSC19k0843; 1415150; NNX16AI47G / NASA; National Aeronautics & Space Administration (NASA) AGS1532207; AGS1602855 / NSF; National Science Foundation (NSF) Jet Propulsion Laboratory
- Language
- English
- Date published
- 06/01/2020
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455366102771
Metrics
1 Record Views