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

S Y Wu; S Y Ye; G Fischer; C M Jackman; J Wang; J D Menietti; B Cecconi; M Y Long

doi:10.1029/2021GL096990

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

Geophys Res Lett. 2022 Mar 16;49(5):e2021GL096990. doi: 10.1029/2021GL096990. Epub 2022 Mar 14.

Authors

S Y Wu¹, S Y Ye¹, G Fischer², C M Jackman³, J Wang¹, J D Menietti⁴, B Cecconi⁵, M Y Long⁶

Affiliations

¹ Department of Earth and Space Sciences Southern University of Science and Technology Shenzhen People's Republic of China.
² Space Research Institute Austrian Academy of Sciences Graz Austria.
³ School of Cosmic Physics Dublin Institute for Advanced Studies Dublin Ireland.
⁴ Department of Physics and Astronomy University of Iowa Iowa City IA USA.
⁵ LESIA, Observatoire de Paris Université PSL CNRS Sorbonne Université Université de Paris Meudon Paris France.
⁶ Department of Space Physics School of Electronic Information Wuhan University Wuhan People's Republic of China.

Abstract

The reflection-by-sheath mechanism of 5 kHz narrowband emissions (NB) at Saturn is confirmed by Cassini observations during several crossings of the magnetopause, which show that the 5 kHz NB can be prevented from escaping Saturn's magnetosphere. The L-O mode 5 kHz NB remained visible in areas of low plasma density but disappeared in regions of high plasma density. In three cases, NB disappeared immediately after the crossings of Saturn's magnetopause. A possible reflected NB event observed near the magnetosheath is discussed. This mechanism can help explain the 5 kHz NB observed at low latitudes outside the Enceladus plasma torus and their upper frequency limit variations. This mechanism significantly improves the current understanding of the 5 kHz NB.