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Multiply reflected standing Alfven waves in the IO torus: Pioneer 10 observations
Author(s) -
Walker Raymond,
Kivelson Margaret
Publication year - 1981
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl008i012p01281
Subject(s) - jovian , physics , amplitude , standing wave , alfvén wave , torus , jupiter (rocket family) , flux tube , plasma , spacecraft , flux (metallurgy) , mach number , astrophysics , magnetic field , geophysics , magnetohydrodynamics , astronomy , magnetic flux , mechanics , optics , planet , geometry , mathematics , materials science , quantum mechanics , saturn , metallurgy
Observations from the Voyager 1 pass by the Io flux tube strongly indicate that large amplitude standing Alfvén waves are generated as Jovian plasma flows past Io. Recently Gurnett and Goertz (1981) have proposed that this Io generated standing Alfvén wave system extends an appreciable way around the Io L‐shell. In this paper, we present observations of magnetic perturbations found in the Pioneer 10 record as it crossed the Io L‐shell. The field perturbations are qualitatively consistent with the passage of the spacecraft through a standing Alfvén wave pattern. The observations imply an Alfvén Mach number of 0.03, which is 1/5 of the value inferred from Voyager 1 observations. This implies a lower plasma density at the time of the Pioneer 10 flyby.