@article{PostbergGruenHoranyietal.2011,
  author    = {Postberg, Frank and Gr{\"u}n, Eberhard and Horanyi, Mihaly and Kempf, Sascha and Krueger, Harald and Schmidt, J{\"u}rgen and Spahn, Frank and Srama, Ralf and Sternovsky, Zoltan and Trieloff, Mario},
  title     = {Compositional mapping of planetary moons by mass spectrometry of dust ejecta},
  series = {Planetary and space science},
  volume    = {59},
  journal   = {Planetary and space science},
  number    = {14},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0032-0633},
  doi       = {10.1016/j.pss.2011.05.001},
  pages     = {1815 -- 1825},
  year      = {2011},
  abstract  = {Classical methods to analyze the surface composition of atmosphereless planetary objects from an orbiter are IR and gamma ray spectroscopy and neutron backscatter measurements. The idea to analyze surface properties with an in-situ instrument has been proposed by Johnson et al. (1998). There, it was suggested to analyze Europa's thin atmosphere with an ion and neutral gas spectrometer. Since the atmospheric components are released by sputtering of the moon's surface, they provide a link to surface composition. Here we present an improved, complementary method to analyze rocky or icy dust particles as samples of planetary objects from which they were ejected. Such particles, generated by the ambient meteoroid bombardment that erodes the surface, are naturally present on all atmosphereless moons and planets. The planetary bodies are enshrouded in clouds of ballistic dust particles, which are characteristic samples of their surfaces. In situ mass spectroscopic analysis of these dust particles impacting onto a detector of an orbiting spacecraft reveals their composition. Recent instrumental developments and tests allow the chemical characterization of ice and dust particles encountered at speeds as low as 1 km/s and an accurate reconstruction of their trajectories. Depending on the sampling altitude, a dust trajectory sensor can trace back the origin of each analyzed grain with about 10 km accuracy at the surface. Since the detection rates are of the order of thousand per orbit, a spatially resolved mapping of the surface composition can be achieved. Certain bodies (e.g., Europa) with particularly dense dust clouds, could provide impact statistics that allow for compositional mapping even on single flybys. Dust impact velocities are in general sufficiently high at orbiters about planetary objects with a radius > 1000 km and with only a thin or no atmosphere. In this work we focus on the scientific benefit of a dust spectrometer on a spacecraft orbiting Earth's Moon as well as Jupiter's Galilean satellites. This 'dust spectrometer' approach provides key chemical and isotopic constraints for varying provinces or geological formations on the surfaces, leading to better understanding of the body's geological evolution.},
  language  = {en}
}
@article{SeissSpahn2011,
  author    = {Seiss, Martin and Spahn, Frank},
  title     = {Hydrodynamics of saturn's dense rings},
  series = {Mathematical modelling of natural phenomena},
  volume    = {6},
  journal   = {Mathematical modelling of natural phenomena},
  number    = {4},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {0973-5348},
  doi       = {10.1051/mmnp/20116409},
  pages     = {191 -- 218},
  year      = {2011},
  abstract  = {The space missions Voyager and Cassini together with earthbound observations revealed a wealth of structures in Saturn's rings. There are, for example, waves being excited at ring positions which are in orbital resonance with Saturn's moons. Other structures can be assigned to embedded moons like empty gaps, moon induced wakes or S-shaped propeller features. Furthermore, irregular radial structures are observed in the range from 10 meters until kilometers. Here some of these structures will be discussed in the frame of hydrodynamical modeling of Saturn's dense rings. For this purpose we will characterize the physical properties of the ring particle ensemble by mean field quantities and point to the special behavior of the transport coefficients. We show that unperturbed rings can become unstable and how diffusion acts in the rings. Additionally, the alternative streamline formalism is introduced to describe perturbed regions of dense rings with applications to the wake damping and the dispersion relation of the density waves.},
  language  = {en}
}
@misc{SeissSpahn2011,
  author    = {Seiß, Martin and Spahn, Frank},
  title     = {Hydrodynamics of Saturn's dense rings},
  series = {Postprints der Universit{\"a}t Potsdam : Postprint Mathematisch Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Postprint Mathematisch Naturwissenschaftliche Reihe},
  doi       = {10.25932/publishup-41313},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-413139},
  pages     = {191 -- 218},
  year      = {2011},
  abstract  = {The space missions Voyager and Cassini together with earthbound observations re-vealed a wealth of structures in Saturn's rings. There are, for example, waves being excited at ring positions which are in orbital resonance with Saturn's moons. Other structures can be assigned to embedded moons like empty gaps, moon induced wakes or S-shaped propeller features. Further-more, irregular radial structures are observed in the range from 10 meters until kilometers. Here some of these structures will be discussed in the frame of hydrodynamical modeling of Saturn's dense rings. For this purpose we will characterize the physical properties of the ring particle ensemble by mean field quantities and point to the special behavior of the transport coefficients. We show that unperturbed rings can become unstable and how diffusion acts in the rings. Additionally, the alternative streamline formalism is introduced to describe perturbed regions of dense rings with applications to the wake damping and the dispersion relation of the density waves.},
  language  = {en}
}