Mass unloading along the inner edge of the Enceladus plasma torus

W. M. Farrell; M. L. Kaiser; D. A. Gurnett; W. S. Kurth; A. M. Persoon; J. E. Wahlund; P. Canu

doi:10.1029/2007GL032306

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Mass unloading along the inner edge of the Enceladus plasma torus

Journal article

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Mass unloading along the inner edge of the Enceladus plasma torus

W. M. Farrell, M. L. Kaiser, D. A. Gurnett, W. S. Kurth, A. M. Persoon, J. E. Wahlund and P. Canu

Geophysical research letters, Vol.35(2), pp.L02203-n/a

01/2008

DOI: 10.1029/2007GL032306

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Abstract

A major discovery made by the Cassini spacecraft at Saturn was the substantial mass ejection from the south pole of Enceladus. Previous studies show that this ejected gas can become ionized and subsequently load mass onto the connecting magnetic field lines near the moon. Radial diffusion then allows the mass-loaded field lines to move outward to similar to 15 R-s and inward to similar to 2 R-s, forming a plasma torus. We demonstrate herein that the mass is also '' unloaded '' along the inner edge of this plasma torus the edge incident with the plasma-absorbing A-ring. Interpreting down-drifting z-mode tones from active sites along the inner edge of the ion torus as emission near the local electron plasma frequency, f(pe), we can remotely-monitor this reduction in plasma density along the torus inner edge as a function time. We find that the down-drift of the z-mode tones corresponds typically to a plasma density change dn/dt similar to - 5x10(-4)/cm(3)-s and when integrated over an annulus defined by the outer edge of the A-ring, corresponds to a mass loss of similar to 40 kg/s. Using the z-mode tones, we also find locations where plasma mass from the ring-ionosphere is possibly loaded at 1 - 2 kg/s onto field lines near the Cassini gap.

Geology

Geosciences, Multidisciplinary

Physical Sciences

Science & Technology

Details

Title: Subtitle: Mass unloading along the inner edge of the Enceladus plasma torus
Creators: W. M. Farrell - Goddard Space Flight Center
M. L. Kaiser - Goddard Space Flight Center
D. A. Gurnett - University of Iowa
W. S. Kurth - University of Iowa
A. M. Persoon - University of Iowa
J. E. Wahlund - Swedish Institute of Space Physics
P. Canu - CETP, F-78140 Velizy Villacoublay, France
Resource Type: Journal article
Publication Details: Geophysical research letters, Vol.35(2), pp.L02203-n/a
Publisher: Amer Geophysical Union
DOI: 10.1029/2007GL032306
ISSN: 0094-8276
eISSN: 1944-8007
Number of pages: 5
Language: English
Date published: 01/2008
Academic Unit: Physics and Astronomy
Record Identifier: 9984455266202771

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