Collisional effects on the numerical recurrence in Vlasov-Poisson simulations
- Dipartimento di Fisica and CNISM, Università della Calabria, 87036 Rende (CS) (Italy)
- Center for Mathematics and Computer Science (CWI), 1090 GB Amsterdam (Netherlands)
The initial state recurrence in numerical simulations of the Vlasov-Poisson system is a well-known phenomenon. Here, we study the effect on recurrence of artificial collisions modeled through the Lenard-Bernstein operator [A. Lenard and I. B. Bernstein, Phys. Rev. 112, 1456–1459 (1958)]. By decomposing the linear Vlasov-Poisson system in the Fourier-Hermite space, the recurrence problem is investigated in the linear regime of the damping of a Langmuir wave and of the onset of the bump-on-tail instability. The analysis is then confirmed and extended to the nonlinear regime through an Eulerian collisional Vlasov-Poisson code. It is found that, despite being routinely used, an artificial collisionality is not a viable way of preventing recurrence in numerical simulations without compromising the kinetic nature of the solution. Moreover, it is shown how numerical effects associated to the generation of fine velocity scales can modify the physical features of the system evolution even in nonlinear regime. This means that filamentation-like phenomena, usually associated with low amplitude fluctuations contexts, can play a role even in nonlinear regime.
- OSTI ID:
- 22493878
- Journal Information:
- Physics of Plasmas, Vol. 23, Issue 2; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Stability and Conservation properties of Hermite-based approximations of the Vlasov-Poisson System
Stability of nonlinear Vlasov-Poisson equilibria through spectral deformation and Fourier-Hermite expansion