Non-Markovian diffusion in plasma turbulence

Journal Article · Sun Aug 01 04:00:00 EDT 1993 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860677· OSTI ID:6171007

Xia, H; Ishihara, O ^[1]; Hirose, A ^[2]

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1. Department of Electrical Engineering, Texas Tech University, Lubbock, Texas 79409-3102 (United States)
2. Department of Physics, University of Saskatchewan, Saskatoon S7N 0W0 (Canada)

Motion of charged particles in electrostatic plasma turbulence is studied analytically and numerically. Analytical study is based on a stochastic differential equation, the generalized Langevin equation, which is derived by the projection operator method with the assumption that the random fluctuation field is a Gaussian and wide sense stationary process. The equation describes the particle velocity as a stochastic process driven by field fluctuations, and is applied to evaluate the velocity diffusion coefficient. The non-Markovian velocity diffusivity is characterized by the retarded turbulent collision term which contributes to the memory effect of the wave--particle interaction. Test-particle numerical experiments are carried out by following trajectories of charged particles in Langmuir turbulence. The observed diffusion coefficient in a relatively strong turbulence deviates from predicted values of the quasilinear and the extended resonance broadening theories. The present non-Markovian formulation explains well such a departure of the diffusion rate.

• OSTI ID: 6171007
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 5:8; ISSN 0899-8221; ISSN PFBPEI
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
BROWNIAN MOVEMENT
DIFFUSION
EQUATIONS
GAUSSIAN PROCESSES
LANGEVIN EQUATION
NUMERICAL SOLUTION
STOCHASTIC PROCESSES
TEST PARTICLES
TURBULENCE
VORTICES