Diffusion of test particles in stochastic magnetic fields for small Kubo numbers

Journal Article · Wed Feb 15 00:00:00 EST 2006 · Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics

DOI:https://doi.org/10.1103/PHYSREVE.73.0· OSTI ID:20778708

Neuer, Marcus; Spatschek, Karl H ^[1]

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1. Institut fuer Theoretische Physik I, Heinrich-Heine-Universitaet Duesseldorf D-40225 Duesseldorf (Germany)

Motion of charged particles in a collisional plasma with stochastic magnetic field lines is investigated on the basis of the so-called A-Langevin equation. Compared to the previously used V-Langevin model, here finite Larmor radius effects are taken into account. The A-Langevin equation is solved under the assumption that the Lagrangian correlation function for the magnetic field fluctuations is related to the Eulerian correlation function (in Gaussian form) via the Corrsin approximation. The latter is justified for small Kubo numbers. The velocity correlation function, being averaged with respect to the stochastic variables including collisions, leads to an implicit differential equation for the mean square displacement. From the latter, different transport regimes, including the well-known Rechester-Rosenbluth diffusion coefficient, are derived. Finite Larmor radius contributions show a decrease of the diffusion coefficient compared to the guiding center limit. The case of small (or vanishing) mean fields is also discussed.

• OSTI ID: 20778708
• Journal Information: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, Vol. 73, Issue 2; Other Information: DOI: 10.1103/PhysRevE.73.026404; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-651X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
APPROXIMATIONS
CHARGED PARTICLES
CHARGED-PARTICLE TRANSPORT
COLLISIONAL PLASMA
CORRELATION FUNCTIONS
DIFFERENTIAL EQUATIONS
DIFFUSION
FLUCTUATIONS
LAGRANGIAN FUNCTION
LANGEVIN EQUATION
LARMOR RADIUS
MAGNETIC FIELDS
MEAN-FIELD THEORY
PLASMA SIMULATION
TEST PARTICLES