Frank Spahn

TL;DR: A model for collisions between particles of a granular material is proposed and it is found that the type of collision is determined by the impact velocity and by the surface properties of the colliding grains.

TL;DR: During Cassini's close flyby of Enceladus on 14 July 2005, the High Rate Detector of the Cosmic Dust Analyzer registered micron-sized dust particles enveloping this satellite; this asymmetric signature is consistent with a locally enhanced dust production in the south polar region of Encesladus.

TL;DR: The Cassini-Huygens Cosmic Dust Analyzer (CDA) is intended to provide direct observations of dust grains with masses between 10-19 and 10-9 kg in interplanetary space and in the jovian and satumian systems, to investigate their physical, chemical and dynamical properties as functions of the distances to the Sun, to Jupiter and to Saturn and its satellites and rings as mentioned in this paper.

TL;DR: It is shown that repeated wall collisions of grains, with re-acceleration by the gas, induce an effective friction, offering a natural explanation for the reduced grain velocity, and suggests liquid water below Enceladus’ south pole.

TL;DR: This work investigates the collision of adhesive viscoelastic spheres in quasistatic approximation where the adhesive interaction is described by the Johnson, Kendall, and Roberts (JKR) theory and describes both restitutive collisions quantified by the coefficient of restitution epsilon as well as aggregative collisions, characterized by the critical aggregative impact velocity gcr.