First observation of lion roar-like emissions in Saturn’s magnetosheath

0474187 - ÚFA 2018 DE eng A - Abstract
Píša, David - Sulaiman, A. H. - Santolík, Ondřej - Hospodarsky, G. B. - Kurth, W. S. - Gurnett, D. A.
First observation of lion roar-like emissions in Saturn’s magnetosheath.
Geophysical Research Abstracts. Göttingen: European Geosciences Union, 2017. EGU2017-682. ISSN 1607-7962.
[EGU General Assembly 2017. 23.04.2017-28.04.2017, Vienna]
Institutional support: RVO:68378289
Keywords : electromagnetic whistler mode waves * magnetosheath * Saturn’s
Subject RIV: BL - Plasma and Gas Discharge Physics
http://meetingorganizer.copernicus.org/EGU2017/EGU2017-682.pdf

Electromagnetic whistler mode waves known as "lion roars" have been reported by many missions inside the
terrestrial magnetosheath. We show the observation of similar intense emissions in Saturn’s magnetosheath as
detected by the Cassini spacecraft. The emissions were observed inside the dawn sector (MLT∼0730) of the magnetosheath
over a time period of nine hours before the satellite crossed the bow shock and entered the solar wind.
The emissions were narrow-banded with a typical frequency of about 15 Hz well below the local electron cyclotron
frequency (fce ∼100 Hz). Using the minimum variance analysis method, we show that the waves are right hand
circularly polarized and propagate at small wave normal angles with respect to the ambient magnetic field. Here,
for the first time, we report the evidence of lion roar-like emissions in Saturn’s magnetosheath which represents a
new and unique parameter regime.
Permanent Link: http://hdl.handle.net/11104/0271296