Quantitative characterization of Enceladus' plume and its variability using hybrid simulations and Cassini magnetometer data

• Applicant: Professor Uwe Motschmann, Ph.D.
• Subject Area: Astrophysics and Astronomy
• Term: from 2011 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 202760827

The purpose of this project is to characterize the plume of Saturn’s moon Enceladus by comparing results from our hybrid simulation code A.I.K.E.F. (adaptive ion kinetic electron fluid) with observations made by the Cassini spacecraft.In a first step, we will analyze the influence of multi-species ion-neutral chemistry on the overall plasma structures and magnetic field: The rates for the reactions of the different water group ions with the water molecules in the plume strongly differ from each other. The resulting changes in the abundances of these ions therefore cause variations of the total reaction rate, which finally determines the magnetic field perturbation caused by the plume. Thus, the different reactions need to be considered for a reasonable interpretation of magnetic field signatures.In a second step, we will incorporate a multi-jet Monte-Carlo model of the plume into our plasma simulation, which will include the measured locations of individual jets as well as gravitational and inertia forces. By comparing the results of our simulations with magnetometer data, we are going to characterize the source strength and variability of the jets for all Enceladus flybys.As a third step, we will exploit the capablity of hybrid models to describe non-Maxwellian velocity distributions. Due to pick-up in the plume, the ions form a ring distribution, which thermalizes by generating ion-cyclotron waves. We will analyze the self-consistent formation of the ring and correlate the associated waves with MAG data in order to provide further insight into the pick-up process at Enceladus.

• DFG Programme: Research Grants
• Participating Person: Professor Dr. Sven Simon