Self-consistent Lagrangian study of nonlinear Landau damping
Résumé
The electric field computed by numerically solving the one-dimensional Vlasov-Poisson system is used to calculate Lagrangian trajectories of particles in the wave-particle resonance region. The analysis of these trajectories shows that, when the initial amplitude of the electric field is above some threshold, two populations of particles are present: a first one located near the separatrix, which performs flights in the phase space and whose trajectories become ergodic and chaotic, and a second population of trapped particles, which displays a nonergodic dynamics. The complex, nonlinear interaction between these populations determines the oscillating long-time behavior of solutions.
Domaines
Astrophysique [astro-ph]
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