摘要:

We first detail the formalism, based on a Boltzmann equation approach, which allows a simplified description of the motion of an electron swarm. We show that, in spite of its simplicity, this formalism is sufficient to obtain the macroscopic parameters measured in actual swarm experiments. This constitutes the so-called hydrodynamic approach and we see that it can be carried out by taking the moments relative to the position space of the continuity equation and of the Boltzmann equation. This technique allows a rigourous definition of the various swarm parameters.

ISSN:0041-1450    

DOI:10.1080/00411458608212713

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Recent analytical results of both time-dependent and time-independent methods are surveyed for inferring the albedo of single scattering and the coefficients of the Legendre expansion of the angle-dependent scattering law. Also presented are some new equations and new approximate solution techniques for the time-independent method that may help reduce the poor conditioning of the numerical solution of the formal ly-exact equations.

ISSN:0041-1450    

DOI:10.1080/00411458608212714

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The problem of formulating and solving linear kinetic (transport) equations in a random maedium is considered. In such a medium, the cross sections and external source are known only in a statistical sense. A projection operator technique is used to derive the appropriate equation for the ensemble averaged distribution function. This equation contains and infinite series, with the nth term involving an n-fold applicaytion of the inverse operator for a non-statistical transport equation. This multiple inverse operator (a multiple integral over Green's functions) acts on various correlation functions describing the statistical nature of the medium. Fokker-Planck approximation can be employed to localize these integral operators.

ISSN:0041-1450    

DOI:10.1080/00411458608212715

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

In the analysis of many reactor experiments the exploitation of the information contained in the fluctuations represents a powerful approach for estimating relevant kinetic parameters together with their corlfidence intervals.

ISSN:0041-1450    

DOI:10.1080/00411458608212716

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This note extends previous results of Mullikin and the author on convergence of the FNmethod to isotropic multi-group problems in half-space geometries.

ISSN:0041-1450    

DOI:10.1080/00411458608212717

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Double-PN transport calculations have generally been thought to give better results than the corresponding (2N-1)-order calculations with the full-range spherical harmonics. especially near boundaries. New radiative transfer calculations in both low and high orders with highly anisotropic scattering bear this out. We examine results given by both methods for a set of standard problems for a haze model with 82 terms in the phase function and for a cloud model with 300 terms i n the phase function.

ISSN:0041-1450    

DOI:10.1080/00411458608212718

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

In the present paper a generalization is performed of a procedure to solve multiqroup spherical har- monics equations, which has originally been proposed and developed for one-dimensional systems in cylindrical or spherical qeometry, and later extended for a special case of a two-dimensional system in r-z aeometry. The expressions are derived for the axial and the radial dependence of the group values of the neutron flux moments, in the P-3 approximation of the spherical harmonics method, in a cylindrically symmetrical system with an arbitrary number of material reqions in both r- and 2-directions. In the special case of an axially homogeneous system, these expressions reduce to the relations derived previously.

ISSN:0041-1450    

DOI:10.1080/00411458608212719

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This paper presents a new method for the solution of neutron transport equation in complex geometry. Using the Rvachev method, a solution structure satisfying exactly the boundary condition is derived. In such a way, information about the geometrical shape of the considered spatial domain is a priori analytically incorporated into the approximate solution. In particular, the construction of domain functions for the most used reactor lattice models (rectangular, triangular and cluster configurations) is given.

ISSN:0041-1450    

DOI:10.1080/00411458608212720

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The Spencer-Lewis equation of electron transport theory with an energy independent screened-Rutherford scattering kernel in an in finite medium is solved using a moment reconstruction technique. The solution is evaluated to a high degree of accuracy for use as a benchmark. The evaluation features general anisotropic scattering for a localized source or for a uniformly distributed source in a half-space.

ISSN:0041-1450    

DOI:10.1080/00411458608212721

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

We shall discuss the existence adn uniqueness of solutins to the equation of transfer of polarized light for a finite or semiinfinite plane-parallel planetary atmospher following two different approaches. In one approach the problem is converted into a vector integral equatin, of convoltion type if reflectin by the planetary surface is ignored, and this equation is analyzed using positive cone preservation techniques. In the second approach the boundary value problem is treated directly using positive selfadjountness of the real part of the stationary transfer operator, where and important role is played by inequalities satisfied by certain expansion coefficients.

ISSN:0041-1450    

DOI:10.1080/00411458608212722

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor