title: Phase transition in the collisionless damping regime for wave-particle interaction
abstract: Gibbs statistical mechanics is derived for the Hamiltonian system coupling a wave to N particles self-consistently. This identifies Landau damping with a regime where a second order phase transition occurs. For nonequilibrium initial data with warm particles, a critical initial wave intensity is found: above it, thermodynamics predicts a finite wave amplitude in the limit N-->infinity; below it, the equilibrium amplitude vanishes. Simulations support these predictions providing new insight into the long-time nonlinear fate of the wave due to Landau damping in plasmas.
authors.affiliation: Equipe turbulence plasma de l'UMR 6633, CNRS-Universite de Provence, case 321, Centre de Saint-Jerome, avenue escadrille Normandie-Niemen, F-13397 Marseille Cedex 20, France.
authors.initials: MC
authors.lastname: Firpo
authors.initials: Y
authors.lastname: Elskens