Journal article
Cassini evidence for rapid interchange transport at Saturn
Planetary and space science, Vol.57(14), pp.1779-1784
12/01/2009
DOI: 10.1016/j.pss.2009.04.010
Abstract
During its tour Cassini has observed numerous plasma injection events in Saturn's inner magnetosphere. Here, we present a case study of one “young” plasma bubble observed when Cassini was in the equatorial plane. The bubble was observed in the equatorial plane at ∼7 Saturn radii from Saturn and had a maximum azimuthal extent of ∼0.25
Rs (Rs=Saturn radius ∼60330
km). We show that the electron density inside the event is lower by a factor ∼3 and the electron temperature higher by over an order of magnitude compared to its surroundings. The injection contains slightly increased magnetic field magnitude of 49
nT compared with a background field of 46
nT. Modelling of pitch angle distributions inside the plasma bubble and measurements of plasma drift provide a novel way to estimate that the bubble originated between 9<
L<11 and had an average radial propagation speed of ∼260+60/−70
km
s
−1. An independent estimate of the speed of the injection following theoretical work of Pontius et al. [1986. Steady State Plasma transport in a Corotation-Dominated Magnetosphere. Geophys. Res. Lett. 13(11), 1097–1100] based on the mass per unit flux gives a maximum radial propagation speeds of 140
km
s
−1. These results are similar to those found by Thorne et al. [1997. Galileo evidence for rapid interchange transport in the Io torus. Geophys. Res. Lett. 24, 2131] for one event observed in Jupiter's magnetosphere near Io. We therefore suggest this is evidence of the same process operating at both planets.
Details
- Title: Subtitle
- Cassini evidence for rapid interchange transport at Saturn
- Creators
- A.M. Rymer - Johns Hopkins University Applied Physics LaboratoryB.H. Mauk - Johns Hopkins University Applied Physics LaboratoryT.W. Hill - Rice UniversityN. André - European Space Research and Technology CentreD.G. Mitchell - Johns Hopkins University Applied Physics LaboratoryC. Paranicas - Johns Hopkins University Applied Physics LaboratoryD.T. Young - Southwest Research InstituteH.T. Smith - Johns Hopkins University Applied Physics LaboratoryA.M. Persoon - University of IowaJ.D. Menietti - University of IowaG.B. Hospodarsky - University of IowaA.J. Coates - University College LondonM.K. Dougherty - Imperial College London
- Resource Type
- Journal article
- Publication Details
- Planetary and space science, Vol.57(14), pp.1779-1784
- Publisher
- Elsevier Ltd
- DOI
- 10.1016/j.pss.2009.04.010
- ISSN
- 0032-0633
- eISSN
- 1873-5088
- Language
- English
- Date published
- 12/01/2009
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455261702771
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