Magnetosphere Seminars

Alfven Wave Propagation in a 3D Model of the Io Plasma Torus

Speaker:Parker Hinton [APS]
Date:Tuesday, Jan 15, 2019
Time:4:00 pm
Location:LASP Space Science Building, room N100 (1st floor)

Seminar Abstract:

We use a combination of in situ plasma data (Voyager 1), physical chemistry, and Cassini UVIS observations to constrain a diffusive equilibrium model of the Io plasma torus (IPT) in three dimensions. The different sections of the IPT include the cold inner torus (disk), a portion between the disk and the orbit of Io (duct or sometimes called the ribbon), and the remaining warmer outer torus (donut). The disk exists from approximately 4 – 5.6 RJ, the duct exists from 5.6 – 6 RJ, and the donut portion extends from 6 – 10 RJ (1 RJ = 71,492 km). In addition to generating a model that captures these dimensions, our model also accounts for a System III variation, mostly in composition, observed by Cassini. This model includes various parameters that can be adjusted in order to gain further insight into the plasma torus. Such parameters include ion and electron temperatures, densities, velocities, and distributions, as well as Jupiter’s magnetic field. The interaction of the IPT with Io launches Alfvén waves from both hemispheres of Io that propagate along the magnetic field lines. We use the recent Juno-based magnetic field model [Connerney et al. 2018] combined with our 3D model of the Io plasma torus to simulate the propagation of these Alfvén waves. We also explore how mass density variation in the Io plasma torus, caused by changes in volcanic activity on Io, might affect the Alfvén travel time. This simulation makes predictions about where the Io auroral footprint will be visible given different locations of Io in Jupiter’s magnetosphere.