[PPS01-P03] Study of the solar wind influence on the Jovian inner magnetosphere using an ionospheric potential solver
Keywords:Jupiter, Io plasma torus
We have constructed a 2-D ionospheric potential solver in order to demonstrate this scenario quantitatively. We investigate how the global distribution of the ionospheric potential changes responding to the input of the FAC using the potential solver. We use the intensity of the total FAC obtained from the Galileo observation [Khurana, 2001] and adopt a Gaussian function for its horizontal distribution in a similar way to the Earth’s modeling. Also, we model the ionospheric conductivities from the collision frequencies, the cyclotron frequencies of charged particles and the density distribution in the Jovian upper atmosphere. We deduce the collision frequencies from ion-H2 and electron-H2 collisions [Tao, 2009]. We need to use more accurate global distributions of the conductivities because the dawn-to-dusk electric field of at Io’s orbit strongly depends on the spatial distributions of the ionospheric conductivities. The limited area of the ionosphere was observed by Galileo and Voyager, therefore we use a Jovian thermosphere-ionosphere-magnetoshere coupling model [Tao et al., 2014] to obtain the global thermospheric and ionospheric distributions of the density and the temperature in this study. The model considers heating caused by the precipitation of aurora electrons and provides the distributions of the conductivities around the footprint of FACs.
We calculate the Jovian electric potential distribution and the magnetospheric dawn-to-dusk electric field for the aforementioned FAC and conductivity distributions. We assume that the plasma of the IPT flow along the equipotential lines. Under this assumption, we estimate the dawnward shift of the equipotential lines which results from the dawn-to-dusk electric field and the corotation field, and the dawn-to-dusk ratio of plasma brightness. The estimated values are compared with the Hisaki observations in order to evaluate the validity of the above scenario. We will present these results.