A Jovian Magnetodisc Model for the Juno Era

• Published in: Journal of geophysical research. Space physics Vol. 125; no. 10; pp. e2020JA028138 - n/a
• Main Authors: Connerney, J. E. P., Timmins, S., Herceg, M., Joergensen, J. L.
• Format: Journal Article
• Language: English
• Published: United States 01.10.2020
• Subjects: Jovian; Juno spacecraft; Jupiter; magnetic field; magnetodisc; magnetosphere; Juno spacecraft; Jupiter; magnetic field; magnetosphere; magnetodisc; Jovian
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1029/2020JA028138

The Jovian magnetosphere assumes a disc‐like geometrical configuration (“magnetodisc”) owing to the persistent presence of a system of azimuthal currents circulating in a washer‐shaped volume aligned with, or near, the magnetic equatorial plane. A Voyager era empirical model of the magnetodisc is fitted to vector magnetic field measurements obtained during the Juno spacecraft's first 24 orbits. The best fitting (within 30 Jovian radii) magnetodisc model is characterized by an inner and outer radius of 7.8 and 51.4 Jovian radii, a half‐thickness of 3.6 Jovian radii, with a surface normal at 9.3° from the Jovigraphic pole and 204.2° System 3 west longitude. We supplement the magnetodisc model with a second current system, also confined to the magnetic equatorial plane, consisting of outward radial currents that presumably effect the transfer of angular momentum to outward flowing plasma. Allowing for variation of the magnetodisc's azimuthal and radial current systems from one 53‐day orbit to the next, we develop an index of magnetospheric activity that may be useful in interpretation of variations in auroral observations. Key Points An empirical magnetodisc model is fitted to the Juno magnetic field observations The magnetodisc model provides a more accurate representation of the magnetic field in the inner and middle magnetosphere of Jupiter The model is independently tested via observations of charged particle interactions with the Jovian satellites