Centrifugal Equator in Jupiter’s Plasma Sheet

• Published in: Journal of geophysical research. Space physics Vol. 126; no. 1
• Main Authors: Phipps, Phillip, Bagenal, Fran
• Format: Journal Article
• Language: English
• Published: 01-01-2021
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1029/2020JA028713

In Jupiter’s magnetosphere, the structure of the plasma sheet depends on the magnetic field geometry and the centrifugal forces on the plasma. We present a simple formulation for the centrifugal equator, the farthest point along a magnetic flux tube from the planetary spin axis, for Jupiter’s torus to plasma sheet region (5–30 jovian radii). The formulation is based on a dipole magnetic field and azimuthally symmetric current sheet, both tilted by 9.5° toward System III west longitude of 201°. We find a good fit to such a model with a hyperbolic tangent function varying sinusoidally with longitude. The latitudinal angle of the derived centrifugal equator relative to the jovigraphic equator changes from the dipolar value (2/3 of the dipole tilt) around 5 jovian radii to close to the full dipole tilt at 25 jovian radii.
Key Points
Between 5 and 30 jovian radii, the equatorial current sheet increasingly changes the magnetic field geometry from a dipole to a disk
The centrifugal equator correspondingly changes from 2/3 to the full magnetic dipole tilt
We derive a simple formulation for the centrifugal equator versus distance and System III longitude