Does fast magnetic reconnection exist?

Journal Article · Sun Nov 01 04:00:00 EST 1992 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/92JA01146· OSTI ID:166710

Priest, E R; Forbes, T G ^[1]

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1. The University, St. Andrews (United Kingdom)

The classical Petschek model of fast, steady state reconnection has been generalized in two families of reconnection regimes. The first family, which the authors refer to as {open_quotes}almost uniform,{close_quotes} models the reconnection of nearly uniform, antiparallel magnetic fields, and it includes Petschek`s model as a special case. The second family, which they refer to as nonuniform, models the reconnection of strongly curved magnetic fields, and it includes separatrix jets and reversed current spikes as the ends of the diffusion region. In general, both families contain regimes having fast reconnection rates, but the authors show here that these fast reconnection regimes do not occur when the boundary conditions often used in numerical experiments are adopted. In 1986, D. Biskamp carried out a series of numerical experiments to check Petschek`s prediction that the maximum reconnection rate should scale with the magnetic Reynolds number, R{sub me}, as [1n (R{sub me})]{sup {minus}1}. Biskamp found that the maximum reconnection rate in his experiments did not scale in this way but instead as R{sub me}{sup {minus}1/2}. Because this corresponds to the scaling predicted by the slow reconnection theory of Sweet and Parker, Biskamp has argued that his numerical experiments show that fast reconnection does not exist at high magnetic Reynolds numbers. However, by applying boundary conditions similar to Biskamp`s to the {open_quotes}nonuniform{close_quotes} family of reconnection regimes, the authors are able to explain Biskamp`s scaling results and to explain why he did not achieve fast reconnection in his numerical experiments. Therefore, they conclude that numerical experiments with suitably designed boundary conditions are highly likely to exhibit fast reconnection and that such reconnection is a common process in astrophysical and space plasmas. 22 refs., 11 figs., 2 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 166710
• Journal Information: Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: A11 Vol. 97; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
EARTH MAGNETOSPHERE
MAGNETIC RECONNECTION
REACTION KINETICS