Survey of intense whistler-mode emissions in Saturn’s magnetosheath

0477554 - ÚFA 2018 SE eng A - Abstract
Píša, David - Sulaiman, A. H. - Santolík, Ondřej - Hospodarsky, G. B. - Kurth, W. S. - Gurnett, D. A.
Survey of intense whistler-mode emissions in Saturn’s magnetosheath.
MOP 2017: Programme Book. Uppsala: Swedish Institute for Space Physics, 2017. s. 15.
[Magnetospheres of the Outer Planets. 12.06.2017-16.06.2017, Uppsala]
Institutional support: RVO:68378289
Keywords : whistler mode waves * Saturn * magnetosphere
Subject RIV: BL - Plasma and Gas Discharge Physics
http://www.irfu.se/mop2017/MOP2017_ProgrammeBook.pdf

Intense whistler-mode emissions known as ”lion-roars” have been already reported by
many missions inside the terrestrial magnetosheath. Recently, we have reported the evidence
of such emissions in Saturn’s magnetosheath. We present a survey of these intense emissions
as detected by the Cassini spacecraft between years 2004 and 2010. We identified eight time
intervals with almost 37 hours of the intense lion-roar-like emissions in the low-band (up to
50 Hz) RPWS/WFR spectrogram. The emissions were observed across the day-side
magnetosheath between magnetic local times from 0730 to 1600. The emissions were
narrow-banded with a typical frequency up to 30 Hz, well below the local electron cyclotron
frequency (100 – 1000 Hz). Using the minimum variance analysis method, we show that the
waves are right hand circularly polarized and propagate at small wave normal angles (<40
degrees) with respect to the ambient magnetic field. Finally, we discuss the statistical
properties of the lion-roar-like emissions at Saturn and compare them to observations at
Earth.
Permanent Link: http://hdl.handle.net/11104/0273872