Variability in the Io Plasma Torus Seen by Juno Radio Occultations

Io's volcanic activity is the dominant source of plasma at Jupiter. This volcanic activity creates Io's atmosphere which is lost to Jupiter's magnetosphere near Io. This material is ionized and picked up by Jupiter's magnetic field and distributed into a torus of plasma around Jupiter, called the Io plasma torus. This plasma can be detected by radio occultations in which the plasma's total electron content affects properties of a spacecraft's radio signal as it propagates through the plasma on the way to the receiver. The total electron content of the Io plasma torus is derived from the dual frequency (Ka and X-band) gravity measurements from the Juno spacecraft during Perijoves 1, 3, 6, and 8. We present the Io plasma torus parameters determined from a fit to the total electron content profiles derived from data taken during Juno Perijoves 3, 6, and 8. We also show comparisons to a model that uses the dipole approximation for the magnetic field and another that uses the VIP4 magnetic field model.