Magnetic Reconnection Rate in Space Plasmas: A Fractal Approach

Journal Article · Fri Oct 26 04:00:00 EDT 2007 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.99.175002· OSTI ID:21024364

Materassi, Massimo ^[1]; Consolini, Giuseppe ^[2]

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1. Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, V. Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy)
2. Istituto di Fisica dello Spazio Interplanetario, Istituto Nazionale di Astrofisica, V. Fosso del Cavaliere 100, I-00133 Rome (Italy)

Magnetic reconnection is generally discussed via a fluid description. Here, we evaluate the reconnection rate assuming a fractal topology of the reconnection region. The central idea is that the fluid hypothesis may be violated at the scales where reconnection takes place. The reconnection rate, expressed as the Alfven Mach number of the plasma moving toward the diffusion region, is shown to depend on the fractal dimension and on the sizes of the reconnection or diffusion region. This mechanism is more efficient than prediction of the Sweet-Parker model and even Petschek's model for finite magnetic Reynolds number. A good agreement also with rates given by Hall MHD models is found. A discussion of the fractal assumption on the diffusion region in terms of current microstructures is proposed. The comparison with in-situ satellite observations suggests the reconnection region to be a filamentary domain.

• OSTI ID: 21024364
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 17 Vol. 99; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DIFFUSION
FRACTALS
MACH NUMBER
MAGNETIC RECONNECTION
MAGNETIC REYNOLDS NUMBER
MAGNETOHYDRODYNAMICS
MICROSTRUCTURE
PLASMA
TOPOLOGY