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ERIC Number: EJ931783
Record Type: Journal
Publication Date: 2011-Jul
Pages: 18
Abstractor: As Provided
Reference Count: 56
ISBN: N/A
ISSN: ISSN-0143-0807
Particle Diffusion in an Inhomogeneous Medium
Bringuier, E.
European Journal of Physics, v32 n4 p975-992 Jul 2011
This paper is an elementary introduction to particle diffusion in a medium where the coefficient of diffusion varies with position. The introduction is aimed at third-year university courses. We start from a simple model of particles hopping on a discrete lattice, in one or more dimensions, and then take the continuous-space limit so as to obtain the differential equation of diffusion. The discrete-step model is next adapted to investigate diffusion by continuous-length steps; the coefficient of diffusion is related to the mean free path. In both the discrete- and continuous-step models, the diffusion law has the Fokker-Planck (instead of Fick) pattern if the jumps are not biased and occur equally likely in all directions. Lastly, three experimental examples of diffusion in inhomogeneous media are examined; the observed law can be of a Fokker-Planck, Fick or hybrid type. (Contains 5 footnotes and 3 figures.)
Institute of Physics Publishing. The Public Ledger Building Suite 929, 150 South Independence Mall West, Philadelphia, PA 19106. Tel: 215-627-0880; Fax: 215-627-0879; e-mail: info@ioppubusa.com; Web site: http://www.iop.org/EJ/journal/EJP
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A