Reflection and Refraction of the L‐O Mode 5 kHz Saturn Narrowband Emission by the Magnetosheath Article - Mars 2022

Si Yuan Wu, Sheng Yi Ye, Georg Fischer, Caitriona M Jackman, J Wang, J D Menietti, Baptiste Cecconi, M Long

Si Yuan Wu, Sheng Yi Ye, Georg Fischer, Caitriona M Jackman, J Wang, J D Menietti, Baptiste Cecconi, M Long, « Reflection and Refraction of the L‐O Mode 5 kHz Saturn Narrowband Emission by the Magnetosheath  », Geophysical Research Letters, mars 2022. ISSN 0094-8276

Abstract

Emissions near 10 kHz are also reported (Menietti et al., 2009), but this needs further study. Case studies have shown that the Z-mode NB (at both 5 and 20 kHz) can be generated by temperature anisotropy and loss cone distributions in the low latitude region interior to the plasma torus, whereas the modulation analysis and direction finding results indicate a possible auroral source (Menietti et al., 2011, 2016, 2018 ; Ye, Gurnett, et al., 2010). More events to check the plasma distribution near the source region will help to further explore the generation of the Z mode NB. According to the Z-mode dispersion relation, the initially generated Z-mode NB would be trapped in a "Channel" formed by the iso-surfaces of the f uh and f L = 0 (f uh upper hybrid frequency, f L = 0 Z-mode cutoff frequency ; Sonwalkar et al., 2004). These "trapped" Z-mode NB can mode convert to the "free space" L-O mode NB at density gradients (Menietti et al., 2019 ; Ye, Menietti, et al., 2010). Due to the blockage of the high density plasma torus (centered at the equatorial plane) generated by the cryovolcanic activity of the moon Enceladus, the L-O mode NB originally generated interior to the plasma torus would propagate to high latitudes unhindered, creating a low latitude shadow zone outside the plasma torus (S. Wu et al., 2021 ; Ye, Menietti, et al., 2010). However, 5 kHz NB is still observed at low latitudes outside the plasma torus. How did these NB bypass the plasma torus ?

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