Source location of saturn's kilometric radiation: The Kelvin-Helmholtz instability hypothesis

A new determination of the location of Saturn's kilometric radiation (SKR) sources is deduced from a limited set of hypotheses: assuming that the radio sources are fixed in latitude and local time, and that SKR is emitted on the X mode near its local cutoff frequency, we obtain source location footprints for northern and southern radio sources. The sources in both hemispheres appear magnetically conjugate and are consistent over the whole SKR frequency range. They are centered about 1300 local time (LT), at magnetic latitudes greater than or equal to 80 degrees, extending toward lower latitudes on the morning side (down to 60 degrees at 0800-0900 LT) and on the evening side (down to 75 degrees at 1900 LT). We interpret these source locations in terms of electron precipitations possibly caused by Kelvin-Helmholtz instability arising on the flanks of the Saturnian magnetopause (mainly the morning one). Constraints on the average SKR beaming are derived.