Asymmetric Hermite method for the velocity dependence of the Vlasov equation
- Univ. of Michigan, Ann Arbor, MI (United States)
The Vlasov-Maxwell equations provide one of the basic kinetic theory descriptions of a plasma; in one dimension and for a single negatively charged species of unit charge and unit mass, and with a neutralizing background of immobile positive charge, where the integrals-{integral}f{alpha} du and - {integral}uf{alpha} du over all velocities u give the charge and current densities. Because of the self-consistent coupling, these equations are nonlinear, and very few exact solutions can be constructed. One challenge in the development of numerical methods for these equations is to produce methods that simultaneously and exactly conserve particles, momentum, and energy in a fully discrete model. I have previously described a pseudospectral method based on Legendre-Gauss-Lobatto collocation which was conservative in the sense that particles, energy, and momentum did not appear or disappear into the grid but could enter and leave the region of phase space being modeled; this is satisfactory for spatial boundaries, where particles can physically enter and exit, but the method had a maximum velocity boundary in phase space that allowed high-energy particles to enter and exit the system, carrying their energy and momentum with them, simply by accelerating or decelerating beyond the maximum speed. In this paper, a method is briefly described based on a nonstandard Hermite expansion in velocity that has no such maximum velocity and that does not suffer the same nonphysical loss of particles.
- OSTI ID:
- 186547
- Report Number(s):
- CONF-950601-; ISSN 0003-018X; TRN: 95:004729-0131
- Journal Information:
- Transactions of the American Nuclear Society, Vol. 72; Conference: Annual meeting of the American Nuclear Society (ANS), Philadelphia, PA (United States), 25-29 Jun 1995; Other Information: PBD: 1995
- Country of Publication:
- United States
- Language:
- English
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