Van der Waals-Zeeman Colloquium

Tuesday, 8 February 2011, 16:00

Statics and Dynamics of Granular Matter under Microgravity

Dr. Matthias Sperl
Institut fuer Materialphysik im Weltraum, Deutsches Zentrum fuer Luft- und Raumfahrt, Koeln, Germany

Granular materials are characterized by the fact that during interparticle collisions some of the kinetic energy is lost. This dissipation leads to novel phase behavior and pattern formation. While both theoretical and numerical work has advanced considerably in recent years, the experimental tests -- especially in 3 dimensions -- are more difficult to perform: Dilute granular systems, granular gases, are highly susceptible to sedimentation and difficult to agitate homogeneously; dense granular systems exhibit anisotropies due to gravity.

It will be shown how microgravity can be used to prepare well-defined non-equilibrium steady states for granular gases. This is achieved by magnetic excitation in the bulk of the system. For dense granular matter the transition from a dynamical state to a packing will be discussed.

Sperl afloat