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Title: Comparison of the telegraph and hyperdiffusion approximations in cosmic-ray transport

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.4953564· OSTI ID:22600126
;  [1]
  1. Department of Mathematics, University of Waikato, P. B. 3105, Hamilton (New Zealand)

The telegraph equation and its generalizations have been repeatedly considered in the models of diffusive cosmic-ray transport. Yet the telegraph model has well-known limitations, and analytical arguments suggest that a hyperdiffusion model should serve as a more accurate alternative to the telegraph model, especially on the timescale of a few scattering times. We present a detailed side-by-side comparison of an evolving particle density profile, predicted by the telegraph and hyperdiffusion models in the context of a simple but physically meaningful initial-value problem, compare the predictions with the solution based on the Fokker–Planck equation, and discuss the applicability of the telegraph and hyperdiffusion approximations to the description of strongly anisotropic particle distributions.

OSTI ID:
22600126
Journal Information:
Physics of Plasmas, Vol. 23, Issue 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
Country of Publication:
United States
Language:
English