A New Ring Current Model for Saturn

Abstract

The ring current of Saturn is obtained by taking the curl of the observed magnetic field. An analytical model of this ring current can then be obtained by fitting it to a lognormal in ρ and a Gaussian in z. Local time dependence is included as a harmonic expansion in ϕ for coefficients of the lognormal; radial dependence is included as a quadratic expansion in ρ of the width of the Gaussian. In this model, the ring current peaks at ~0.25 MA/RS2 at ~10 RS on the nightside near ~1 hr. The ring current strength minimizes at ~0.17 MA/RS2 on the dayside near ~16 hr. The cross‐sectional shape of the ring current is a teardrop extending from ~5 to ~20 RS or more.

Saturn’s nightside ring current during Cassini’s Grand Finale

“…Carbary (2019) determined averaged empirical models of the thickness of the ring current from Cassini's magnetic field data. We find that the Staniland et al (2020) ring current agrees with the more intense ring current region determined by Carbary (2019). The maximum thickness of the ring current detected here on the proximal Revs is slightly smaller than the outer boundary region presented by Carbary (2019).…”

“…To investigate this discrepancy in thickness further we return to Figure 2b, showing the thickness of the ring current in the midnight sector modeled by Carbary (2019). Our initial ring current model, comprising four CAN discs with initial thickness of 2, 2.5, 2 and 1 R s centered on the warped magnetodisc equator, is overplotted in Figure 2b as shaded white blocks.…”

Saturn's Nightside Ring Current During Cassini's Grand Finale

“…When plotting our current sheet model we define z=0 Rs as the center of the warped current sheet (Arridge et al, 2008), with the modeled ring current extending symmetrically either side. We note that the Carbary (2019)…”

“…To investigate this discrepancy in thickness further we return to Figure 2b, showing the thickness of the ring current in the midnight sector modeled by Carbary (2019). Our initial ring current model, comprising four CAN discs with initial thickness of 2, 2.5, 2 and 1 Rs centred on the Arridge et al (2008) warped magnetodisc equator, is overplotted on Figure 2b as shaded white blocks.…”

“…Another method of modelling Saturn's ring current was presented by Carbary et al (2012) and Carbary (2019), with Carbary's (2019) 10.1029/2020JA028605…”