Dynamik von Staubteilchen in Saturns E-Ring

• Main Author: Beckmann, U.
• Format: Doctoral or Postdoctoral Thesis
• Language: German
• Published: Ruprecht-Karls-Universität 2008
• Subjects: South Pole; South pole
• Online Access: http://hdl.handle.net/11858/00-001M-0000-0011-79A9-E; http://hdl.handle.net/11858/00-001M-0000-0011-79A8-0

This thesis covers the dynamical evolution of dust in the outer Saturnian magnetosphere, the region of the large E ring. For the dynamical evolution a model is used, which considers the gravitation of Saturn, including the quadrupolmomentum due to Saturns oblateness, the gravi- tation of Saturns large moons embedded in the E ring, the influence of the surrounding plasma as charging of the grains and sputtering, the Lorenz force due to Saturns rotating magnetic field, and the radiation pressure caused by the sun. In this model, the charge of the grain is characterised by time depended charge currents. The material parameters are derived from the comparison with measurements of the grain potential by the dust analyser onboard the spacecraft Cassini. Further measurements done by various scientific instruments of Cassini discover a geologic active south pole on the icy moon Enceladus. This dust plumes are determined as the main source of fresh E ring particle. Dynamical simulations of dust grains launched at the position of the detected plumes determined the minimal ejection speed of the particles necessary to be- come ring particles. The ejection speed is directly related to the ring thickness near Enceladus orbit. Long time evolution of dust dynamic showed, that dust particles launched from Enceladus populate the E ring. Thereby the dynamical dynamical evolution is strongly affected by the radial dependence of the potential. A global model of the E ring could derived from the time evolution of thousands of individual particles. This model is used to predict impact rates of an in situ detector flying through the E ring.