Volume 78, Number 6, June 2007
Article Number 65001
Number of page(s) 6
Section Physics of Gases, Plasmas and Electric Discharges
Published online 25 May 2007
EPL, 78 (2007) 65001
DOI: 10.1209/0295-5075/78/65001

Wave-particle interactions in collisionless plasmas: The failure of Vlasov approximation in describing the approach to statistical equilibrium

V. Carbone, R. De Marco, F. Valentini and P. Veltri

Dipartimento di Fisica, Università della Calabria, and CNISM, Sezione di Cosenza - 87036 Rende (CS), Italy

received 26 February 2007; accepted in final form 3 May 2007; published June 2007
published online 25 May 2007

We investigate the dynamical approach towards equilibrium during the wave-particle interaction process in plasmas. Particle in Cell (PIC) simulations are compared with a Fermi-like model where particle trapping is described as elastic collisions of particles with two barriers whose amplitude is proportional to the energy of the wave. The system approaches statistical equilibrium through a phase mixing described by a filamentation of the phase space, a dynamical system analogous of the Gibbs process of laminar mixing. The system of trapped particles evolves towards the state of maximum entropy and wave-particle interaction creates correlations in the phase space particle trajectories, making Vlasov equation fail in describing the system dynamics.

52.20.-j - Elementary processes in plasmas.
05.45.-a - Nonlinear dynamics and chaos.
52.65.Rr - Particle-in-cell method.

© Europhysics Letters Association 2007