Premium
Local Time Asymmetries in Jupiter's Magnetodisc Currents
Author(s) -
Lorch C. T. S.,
Ray L. C.,
Arridge C. S.,
Khurana K. K.,
Martin C. J.,
Bader A.
Publication year - 2020
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2019ja027455
Subject(s) - magnetosphere , physics , jovian , noon , dynamo , azimuth , magnetohydrodynamic drive , current (fluid) , geophysics , ionosphere , jupiter (rocket family) , magnetohydrodynamics , astrophysics , magnetic field , computational physics , planet , atmospheric sciences , astronomy , saturn , spacecraft , quantum mechanics , thermodynamics
Abstract We present an investigation into the currents within the Jovian magnetodisc using all available spacecraft magnetometer data up until 28 July 2018. Using automated data analysis processes as well as the most recent intrinsic field and current disk geometry models, a full local time coverage of the magnetodisc currents using 7,382 lobe traversals over 39 years is constructed. Our study demonstrates clear local time asymmetries in both the radial and azimuthal height‐integrated current densities throughout the current disk. Asymmetries persist within 30 RJwhere most models assume axisymmetry. Inward radial currents are found in the previously unmapped dusk and noon sectors. Azimuthal currents are found to be weaker in the dayside magnetosphere than the nightside, in agreement with global magnetohydrodynamic simulations. The divergence of the azimuthal and radial currents indicates that downward field‐aligned currents exist within the outer dayside magnetosphere. The presence of azimuthal currents is shown to highly influence the location of the field‐aligned currents, which emphasizes the importance of the azimuthal currents in future magnetosphere‐ionosphere coupling models. Integrating the divergence of the height‐integrated current densities, we find that 1.87 MA RJ − 2of return current density required for system closure is absent.