Alfven wave propagation in the Io plasma torus
Gurnett and Goertz (1981) proposed that the large number of discrete arcs observed in the Jovian decametric radio emission is caused by multiple reflections of Alfven waves excited by Io. In this paper the plasma measurements that were made by the Voyager I plasma science experiment have been combined with a model of Jupiter's magnetic field to calculate the time an Alfven wave takes to travel between Io and Jupiter's ionosphere and the period of subsequent bounces between the northern and southern hemispheres. The result is a wave pattern extending around Jupiter as the multiply reflected Alfven waves are carried away from Io by the corotating magnetospheric plasma. Although the whole pattern continually changes over the 13 hours Io takes to move through 360/sup 0/ of Jovigraphic longitude, a general longitudinal structure is exhibited independent of the position of Io, due to the geometry of the magnetic field and the distribution of plasma in the Io torus. If the Alfven waves stimulate the decametric radio emission, then the wave pattern predicts specific properties of the decametric emission which can be compared with radio observations.
- Research Organization:
- Center for Space Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- OSTI ID:
- 6035082
- Journal Information:
- J. Geophys. Res.; (United States), Vol. 88:A4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
JUPITER PLANET
ALFVEN WAVES
MAGNETIC FIELDS
PLANETARY MAGNETOSPHERES
PLASMA
RADIOWAVE RADIATION
SATELLITES
WAVE PROPAGATION
ATMOSPHERES
ELECTROMAGNETIC RADIATION
HYDROMAGNETIC WAVES
PLANETARY ATMOSPHERES
PLANETS
RADIATIONS
640107* - Astrophysics & Cosmology- Planetary Phenomena