A generalized Fokker-Planck model applied to beam transport

Journal Article · Thu Dec 31 04:00:00 EST 1998 · Transactions of the American Nuclear Society

OSTI ID:298297

Prinja, A K ^[1]; Pomraning, G C ^[2]

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1. Univ. of New Mexico, Albuquerque, NM (United States)
2. Univ. of California, Los Angeles, CA (United States)

In this paper the authors consider a generalized Fokker-Planck (GFP) model for the transport of charged-particle beams, when scattering is not sufficiently forward peaked for the well-known Fokker-Planck (FP) approximation to hold. This approximation is strictly valid in the limit that the total scattering cross section {sigma}{sub s} {r_arrow} {infinity} and the mean cosine of scattering {bar {mu}} {r_arrow} 1. When scattering is not sufficiently forward peaked, higher order Fokker-Planck expansions, restricted to differential cross sections that fall off sufficiently rapidly, can be developed. For instance, the Henyey-Greenstein differential cross section does not possess an FP limit at all, while the screened Rutherford cross section satisfies the FP limit only marginally, and its higher order FP limits do not exist. For cross sections that fall off faster than screened Rutherford, including the exponential phase function, higher order truncations exist.

• OSTI ID: 298297
• Report Number(s): CONF-981106--
• Journal Information: Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 79; ISSN 0003-018X; ISSN TANSAO
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BEAM TRANSPORT
CHARGED-PARTICLE TRANSPORT
FOKKER-PLANCK EQUATION
MATHEMATICAL MODELS
SCATTERING
SLABS