Description
(Text)
Saturns magnetosphere is filled with plasma. This thesis analyzes the high energy part of this plasma, namely protons and electrons at energies between several tens of keV and several tens of MeV. Measurements are used that were obtained by the MIMI/LEMMS instrument onboard the Cassini spacecraft during seven years in orbit. These data are averaged over the mission and presented in several useful ways. The aim of this thesis is to understand the distribution of particles in space and energy. The inner part of the magnetosphere, which is the radiation belts, is successfully modeled. This allows to constrain the parameters of the main processes. It is found that their timescales range from years to hundreds of years. Several pieces of evidence suggest that the protons of the belts are tertiary particles from the interaction of cosmic rays with Saturns atmosphere (CRAND). After production, they are subject to radial diffusion, and losses at the moon orbits. The middle magnetosphere,radially outward from the radiation belts, is also studied. A large variety of physical processes act there. The focus is on the region seven Saturn radii away from the planets center, where the strength of the processes is estimated. This includes a proper treatment of particles losing energy in macroscopic ice grains of the tenuous rings. Source processes, potentially related to injection events, are found to be active in this region. Energetic protons below 1MeV are lost via charge exchange with the neutral gas environment, not the E ring. Below 100 keV, this has a strong effect on their radial profiles.
(Extract)
Space weather and space weathering have an impact on the life of a technically advanced civilization. A harmless but well-known result from space weather is the aurora. This is caused by electrons that follow the Earths magnetic field lines into the atmosphere, where they excite atoms and ions, which then emit light of typical colors. Less well-known is the fact that space weathering is causing damage and temporary failures on satellites. This happens for example because the satellites can charge up until a strong electrical discharge occurs. Energetic particles can flip bits in the memory and cause errors. Over time, the radiation destroys electronic components. Space weather influences the regular weather since cosmic rays ionize the stratosphere and by this produce condensation cores for clouds.
