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Polarization measurements of Saturn Electrostatic Discharges with Cassini/RPWS below a frequency of 2 MHz
Journal article   Open access   Peer reviewed

Polarization measurements of Saturn Electrostatic Discharges with Cassini/RPWS below a frequency of 2 MHz

Georg Fischer, Donald A. Gurnett, Alain Lecacheux, Wolfgang Macher and William S. Kurth
Journal of geophysical research. Space physics, Vol.112(A12), pp.12308-n/a
12/2007
DOI: 10.1029/2007JA012592
url
https://doi.org/10.1029/2007JA012592View
Published (Version of record) Open Access

Abstract

Early in 2006 the RPWS (Radio and Plasma Wave Science) instrument and the ISS (Imaging Science Subsystem) onboard the Cassini spacecraft detected a lightning storm on Saturn that lasted for about one month. The RPWS measured the so-called SEDs (Saturn Electrostatic Discharges), which are high frequency radio signals produced by lightning discharges. The ISS imaged a remarkable cloud system associated with these SEDs at a latitude of 35° South. Below the frequency of 1825 kHz the RPWS was in a mode capable of measuring the polarization of the SEDs. A surprising result was gained; SEDs appeared to be highly polarized (80%) and were exclusively right-handed polarized with a high degree of circular polarization. We will present an explanation for this diagnosis involving magneto-ionic modes and their differential absorption in the magnetoplasma of Saturn's ionosphere.
Astrophysics Physics

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