Equation of state of a granular gas homogeneously driven by particle rotations
Univ Paris Diderot, Sorbonne Paris Cité, MSC, UMR 7057 CNRS - F-75013 Paris, France, EU
Received: 18 June 2013
Accepted: 17 September 2013
We report an experimental study of a dilute “gas” of magnetic particles subjected to a vertical alternating magnetic field in a 3D container. Due to the torque exerted by the field on the magnetic moment of each particle, a spatially homogeneous and chaotic forcing is reached where only rotational motions are driven. This forcing differs significantly from boundary-driven systems used in most previous experimental studies on non-equilibrium dissipative granular gases. Here, no cluster formation occurs, and the equation of state displays a strong analogy with the usual gas one apart from a geometric factor. Collision statistics is also measured and shows an exponential tail for the particle velocity distribution. Most of these observations are well explained by a simple model which uncovers out-of-equilibrium systems undergoing uniform “heating”.
PACS: 45.70.-n – Granular systems / 05.20.Dd – Kinetic theory / 75.50.-y – Studies of specific magnetic materials
© EPLA, 2013