Day-night asymmetries of low-energy electrons in Saturn's inner magnetosphere

We examine the day-night asymmetry of near-equatorial low energy (12-100 eV) electron fluxes measured by Cassini from July 1, 2004 through April 1, 2010. This energy range is also known to be associated with interchange injections. The electrons are separated into field-aligned (0 degrees to 20 degrees and 160 degrees to 180 degrees) pitch angles and trapped (70 degrees to 110 degrees) pitch angles. There is a stronger day-night asymmetry for the trapped than the field-aligned electrons, but both show enhanced energy fluxes on the nightside relative to the dayside. The dayside electron fluxes decrease sharply at an L-shell of 8, while the nightside electrons exhibit a slow decline in to L = 5. Our finding, along with previous research of high energy electrons, shows that this asymmetry is energy independent. This suggests that interchange injections are stronger, and therefore penetrate deeper into the magnetosphere, on the nightside. Citation: DeJong, A. D., J. L. Burch, J. Goldstein, A. J. Coates, and F. Crary (2011), Day-night asymmetries of low-energy electrons in Saturn's inner magnetosphere, Geophys. Res. Lett., 38, L08106, doi: 10.1029/2011GL047308.