An Explicit Energy-Conserving Particle Method for the Vlasov-Fokker-Planck Equation

Abstract

We propose an explicit particle method for the Vlasov-Fokker-Planck equation that conserves energy at the fully discrete level. The method features two key components: a deterministic and conservative particle discretization for the nonlinear Fokker-Planck operator (also known as the Lenard-Bernstein or Dougherty operator), and a second-order explicit time integrator that ensures energy conservation through an accuracy-justifiable correction. We validate the method on several plasma benchmarks, including collisional Landau damping and two-stream instability, demonstrating its effectiveness.