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Research output: Contribution to Journal/Magazine › Conference article › peer-review
Research output: Contribution to Journal/Magazine › Conference article › peer-review
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TY - JOUR
T1 - Testing the relationship between Saturn's ENA and narrowband radio emissions
AU - Kinrade, Joe
AU - Badman, Sarah
AU - Paranicas, Chris
AU - Jackman, Caitriona
AU - Louis, Corentin
AU - O'Dwyer, Elizabeth
N1 - Proceedings of the 9th International Workshop on Planetary, Solar and Heliospheric Radio Emissions, held at Dublin, Ireland, September 26-28 2022.
PY - 2023/7/14
Y1 - 2023/7/14
N2 - Saturn’s kilometric radiation (SKR) and Energetic Neutral Atom (ENA) emissions are important remote diagnostics of the planet’s magnetospheric dynamics, intensifying during periods of global-scale plasma injection, and displaying characteristic planetary periodicity. Global-scale ENA signatures have been associated with narrowband radio emissions around 5 and 20 kHz, particularly at evening local times where plasma injections are expected to have moved inwards through the magnetosphere, triggering interchange instabilities. Narrowband radio emission sources are associated with density gradients at the inner edges of the Enceladus plasma torus that promote wave mode conversion, but any radial distance dependence with the ENA emission is untested. We constrain ENA keograms to distances covering the ‘inner’ and ‘outer’ magnetosphere separately, and quantify the correlation between the ENA intensity with narrowband flux density in the 5 and 20 kHz emission bands. One case study shows a spiral ENA morphology that indicates global-scale plasma injection activity. ‘Bursts’ of narrowband emission coincide with the rotation of ENA enhancements through the dusk-midnight local time sector in the inner magnetosphere, but at earlier times in the outer magnetosphere, consistent with inward flow of the injected plasma as it drifts around the planet. A second case study with similar observing conditions shows clear 5 kHz radio bursts, but very low levels of ENA detections, indicating that the relationship is not always so general in these data. These results contribute towards our developing picture of how global plasma injection events can influence Saturn’s inner magnetosphere, linking together two valuable sources of remotely sensed global emissions, the ENAs and narrowband radio emissions.
AB - Saturn’s kilometric radiation (SKR) and Energetic Neutral Atom (ENA) emissions are important remote diagnostics of the planet’s magnetospheric dynamics, intensifying during periods of global-scale plasma injection, and displaying characteristic planetary periodicity. Global-scale ENA signatures have been associated with narrowband radio emissions around 5 and 20 kHz, particularly at evening local times where plasma injections are expected to have moved inwards through the magnetosphere, triggering interchange instabilities. Narrowband radio emission sources are associated with density gradients at the inner edges of the Enceladus plasma torus that promote wave mode conversion, but any radial distance dependence with the ENA emission is untested. We constrain ENA keograms to distances covering the ‘inner’ and ‘outer’ magnetosphere separately, and quantify the correlation between the ENA intensity with narrowband flux density in the 5 and 20 kHz emission bands. One case study shows a spiral ENA morphology that indicates global-scale plasma injection activity. ‘Bursts’ of narrowband emission coincide with the rotation of ENA enhancements through the dusk-midnight local time sector in the inner magnetosphere, but at earlier times in the outer magnetosphere, consistent with inward flow of the injected plasma as it drifts around the planet. A second case study with similar observing conditions shows clear 5 kHz radio bursts, but very low levels of ENA detections, indicating that the relationship is not always so general in these data. These results contribute towards our developing picture of how global plasma injection events can influence Saturn’s inner magnetosphere, linking together two valuable sources of remotely sensed global emissions, the ENAs and narrowband radio emissions.
U2 - 10.25546/103101
DO - 10.25546/103101
M3 - Conference article
SP - 355
EP - 367
JO - Planetary Radio Emissions IX
JF - Planetary Radio Emissions IX
ER -