Computer Physics Communications Program LibraryPrograms in Physics & Physical Chemistry |

[Licence| Download | New Version Template] aaqu_v3_0.gz(65 Kbytes) | ||
---|---|---|

Manuscript Title: FPPAC88: a two-dimensional multispecies nonlinear Fokker-Planck
package. | ||

Authors: A.A. Mirin, M.G. McCoy, G.P. Tomaschke, J. Killeen | ||

Program title: FPPAC88 | ||

Catalogue identifier: AAQU_v3_0Distribution format: gz | ||

Journal reference: Comput. Phys. Commun. 51(1988)373 | ||

Programming language: Fortran. | ||

Computer: CRAY-1. | ||

Operating system: CTSS. | ||

RAM: 250K words | ||

Word size: 64 | ||

Keywords: Plasma physics, Kinetic model, Two-dimensional, Multispecies, Implicit, Nonlinear, Fokker-Planck. | ||

Classification: 19.8. | ||

Nature of problem:The complete nonlinear multispecies Fokker-Planck collision operator for a plasma in two-dimensional velocity space is solved. The operator is expressed in terms of spherical coordinates (v=speed, theta=angle between velocity and magnetic field directions, phi=azimuthal angle) under the assumption of azimuthal symmetry. Provision is made for additional physics contributions. | ||

Solution method:The Fokker-Planck equation is solved using finite differences. Spatial derivatives are approximated by central differences, with the exception of the advective terms which are approximated by combined central/upwind formulae designed to accommodate situations in which advection dominates diffusion. Time-advancement is accomplished through either implicit operator splitting, an alternating direction implicit (ADI) algorithm, or fully implicit differencing. (In the latter case the user must supply his own nine-banded linear systems solver.) The Fokker-Planck coefficients and their derivatives are computed by expanding the distribution functions and the Rosenbluth potentials in Legendre series, and equating the respective series coefficients. | ||

Reasons for new version:The most important new feature is the modification of the spatial differencing to accommodate situations in which advection dominates diffusion (e.g. the slowing down of 14 MeV fusion protons in a deuteron background). Another important change is the discontinuance of the CDC- 7600 version of FPPAC; thus the NEW VERSION, FPPAC88, is applicable to machines with a single fast memory, in particular the Cray-1 with the CFT compiler. | ||

Restrictions:The user must specify the number of meshpoints in the two coordinate directions as well as the number of Legendre polynomials used to calculate the Fokker-Planck coefficients. Sufficient accuracy for most problems is attainable on the Cray-1. However, double precision should be used on a 32-bit-word machine. | ||

Unusual features:None | ||

Running time:9.6 ms/meshpoint/species on the Cray-1 are required to compute the Fokker-Planck coefficients. 1.9 ms/meshpoint are required to time- advance the distribution function for one species using implicit operator splitting. These times vary to some extent with the mesh configuration due to variations in vectorization efficiency. |

Disclaimer | ScienceDirect | CPC Journal | CPC | QUB |