A Jovian Magnetodisc Model for the Juno Era

Area of Science:

• Planetary Science
• Space Physics
• Magnetospheric Physics

Background:

• Jupiter's magnetosphere exhibits a disc-like structure, known as a magnetodisc.
• This structure is maintained by azimuthal currents within a washer-shaped region near the magnetic equatorial plane.

Purpose of the Study:

• To refine an empirical model of Jupiter's magnetodisc using Juno spacecraft data.
• To incorporate additional current systems and develop an index for magnetospheric activity.

Main Methods:

• Fitting a Voyager-era empirical magnetodisc model to Juno's vector magnetic field measurements.
• Supplementing the model with outward radial currents in the magnetic equatorial plane.
• Analyzing variations in current systems across 24 Jovian orbits.

Main Results:

• A best-fit magnetodisc model was determined within 30 Jovian radii.
• Key parameters include inner/outer radii (7.8/51.4 Rj), half-thickness (3.6 Rj), and surface normal orientation.
• An index of magnetospheric activity was developed based on observed current variations.

Conclusions:

• The study provides a refined model of Jupiter's magnetodisc.
• The developed activity index may aid in understanding auroral variations.
• Observed current system variations highlight dynamic processes within Jupiter's magnetosphere.