Solving the Vlasov equation for one-dimensional models with long range interactions on a GPU

We present a GPU parallel implementation of the numeric integration of the Vlasov equation in one spatial dimension based on a second order time-split algorithm with a local modified cubic-spline interpolation. We apply our approach to three different systems with long-range interactions: the Hamiltonian Mean Field, Ring and the self-gravitating sheet models. Speedups and accuracy for each model and different grid resolutions are presented

Towards a classification of bifurcations in Vlasov equations

We propose a classification of bifurcations of Vlasov equations, based on the strength of the resonance between the unstable mode and the continuous spectrum on the imaginary axis. We then identify and characterize a new type of generic bifurcation where this resonance is weak, but the unstable mode couples with the Casimirs, which are constants of motion, to form a size 3 Jordan block. We derive a three-dimensional reduced noncanonical Hamiltonian system describing this bifurcation: coupling with the Casimirs controls the phase space portrait. Comparison of the reduced dynamics with direct numerical simulations on a test case gives excellent agreement. We finally discuss the relevance of this bifurcation to specific physical situations.Comment: 6 pages, 2 figures. Supplemental material available at the URL https://www.idpoisson.fr/barre/publications-et-preprints