An empirical model of the current sheet in Jupiter's magnetosphere

Abstract

Based on the Magnetometer data from the Galileo and Juno mission, we construct an analytical ring current model that provides the azimuthal current (Jφ) distribution in radial (ρ), height (z), and local time (LT) dimensions. After binning the in-situ magnetic field data into 2 RJ ​× ​2 RJ ​× ​3 ​h (RJ is the radius of Jupiter) bins, the three-dimensional Jφ is calculated by differencing of grid values from the Maxwell equation. The modeled Jφ is obtained by fitting it to a lognormal distribution in ρ and a Gaussian distribution in z. The local time dependence is included by fitting the coefficients of the lognormal using a harmonic expansion. The results show a local time asymmetry of the ring current. Jφ is weaker and the current sheet is compressed at the noon and dusk sectors, comparing with the situation at the midnight and dawn sectors. The ring current peaks at ∼1.5MA/RJ2(2.94×10−1nA/m2) near midnight. Furthermore, the current sheet is thickest near ρ ​= ​10 RJ. The thickness decrease with ρ when ρ ​< ​35 RJ and increase slightly again when ρ ​> ​35 RJ. This empirical model of Jupiter's current sheet is more realistic than previous models.