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Inflow Speed Analysis of Interchange Injections in Saturn's Magnetosphere
Author(s) -
Paranicas C.,
Thomsen M. F.,
Kollmann P.,
Azari A. R.,
Bader A.,
Badman S. V.,
Dumont M.,
Kinrade J.,
Krupp N.,
Roussos E.
Publication year - 2020
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2020ja028299
Subject(s) - saturn , magnetosphere , inflow , physics , planet , plasma , spacecraft , orbit (dynamics) , mechanics , geodesy , computational physics , aerospace engineering , astrophysics , astronomy , geology , nuclear physics , engineering
During its more than 13 years in orbit, the Cassini spacecraft detected a large number of plasma and energetic charged particle injections in Saturn's inner magnetosphere. In the corotating frame of the planet, the plasma contained within an injection moves radially inward with the component particles gaining energy. The highest energy particles in the injection experience stronger gradient‐curvature drifts in the longitudinal direction and can drift out of the main body of the injection. We have used these drift‐out effects to estimate the inflow speed of 20 injections by surveying cases from the available plasma data. We find that the average inflow speed from our sample is 15 km/s, and the values are well distributed between 0 and 50 km/s, with a few higher estimates. We have also computed the radial travel distance of interchange events and found that these are typically one to two Saturn radii. We discuss the implications of these quantifications on our understanding of transport.