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# Superdiffusion revisited in view of collisionless reconnection

Treumann, R. A., and W. Baumjohann (2014), Superdiffusion revisited in view of collisionless reconnection, Annales Geophysicae, 32, 643-650, doi:10.5194/angeo-32-643-2014, 10 Journal pages, 2 figures; Appendix published only in the arXiv:1401.2519, OPEN ACCESS.

Abstract
The concept of diffusion in collisionless space plasmas like those near the magnetopause and in the geomagnetic tail during reconnection is reexamined making use of the division of particle orbits into waiting orbits and break-outs into ballistic motion lying at the bottom, for instance, of L\'evy flights. The rms average displacement in this case increases with time, describing superdiffusion, though faster than classical, is still a weak process, being however strong enough for supporting fast reconnection. Referring to two kinds of numerical particle-in-cell simulations we determine the anomalous diffusion coefficient, the anomalous collision frequency on which the diffusion process is based, and construct a relation between the diffusion coefficients and the resistive scale. The anomalous collision frequency from electron pseudo-viscosity in reconnection turns out of being of the order of the lower-hybrid frequency with the latter providing a lower limit, thus making similar assumptions physically meaningful. Tentative though not completely justified use of the $\kappa$ distribution yields $\kappa\approx 6$ in the reconnection diffusion region, and the anomalous diffusion coefficient the order of several times Bohm diffusivity.
Further information
BibTeX
@article{id1947,
author = {R. A. Treumann and W. Baumjohann},
journal = {Annales Geophysicae},
month = {may},
note = {10 Journal pages, 2 figures; Appendix published only in the arXiv:1401.2519, OPEN ACCESS},
pages = {643-650},
title = {{Superdiffusion revisited in view of collisionless reconnection}},
volume = {32},
year = {2014},
doi = {10.5194/angeo-32-643-2014},
}
EndNote
%0 Journal Article
%A Treumann, R. A.
%A Baumjohann, W.
%D 2014
%V 32
%J Annales Geophysicae
%P 643-650
%Z 10 Journal pages, 2 figures; Appendix published only in the arXiv:1401.2519, OPEN ACCESS
%T Superdiffusion revisited in view of collisionless reconnection