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Manuscript Title: SIGV5D, a routine to compute the reaction rates of interacting distribution functions.
Authors: A.A. Mirin, M.G. McCoy
Program title: SIGV5D
Catalogue identifier: ABFG_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 51(1988)369
Programming language: Fortran.
Computer: CRAY-1.
Operating system: CTSS.
RAM: 70K words
Word size: 64
Keywords: Plasma physics, Kinetic model, Reactivity, Sigma-v, Anisotropic Distributions.
Classification: 19.8.

Nature of problem:
SIGV5D computes reaction rates <sigmav> based on interactions whose cross-sections sigma are functions of relative velocity. The reacting species are described by velocity-space distribution functions, which when expressed in terms of spherical coordinates in velocity space (v, theta, phi), are assumed to be independent of the azimuthal angle phi. One may compute <sigmav> for several different reactions simultaneously and for several sets of distribution functions.

Solution method:
A judicious choice of coordinate system allows the six-dimensional integral to be written as a five-dimensional integral (hence the name SIGV5D). A Legendre expansion method reduces the five-dimensional integral to a triple sum. Two of the terms in this triple sum involve the Legendre coefficients of the distribution functions, and the third term involves an integral over the cross-section, which need not be reevaluated as the distribution functions vary. The numerical integrals are computed using a trapezoidal formula.

Restrictions:
None. It is up to the user to supply subprograms for setting up the mesh, defining the distribution functions and computing the reaction cross-sections.