Statistical and spectral properties of magnetic islands in reconnecting current sheets during two-ribbon flares

Journal Article · Mon Jul 15 00:00:00 EDT 2013 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4816711· OSTI ID:22227933

Shen, Chengcai ^[1]; Lin, Jun ^[1]; Murphy, Nicholas A.; Raymond, John C. ^[2]

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1. Yunnan Astronomical Observatory, Chinese Academy of Sciences, P.O. Box 110, Kunming, Yunnan 650011 (China)
2. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 (United States)

We perform a set of two dimensional resistive magnetohydrodynamic simulations to study the reconnection process occurring in current sheets that develop during solar eruptions. Reconnection commences gradually and produces small-scale structures inside the current sheet, which has one end anchored to the bottom boundary and the other end open. The main features we study include plasmoids (or plasma blobs) flowing in the sheet, and X-points between pairs of adjacent islands. The statistical properties of the fine structure and the dependence of the spectral energy on these properties are examined. The flux and size distribution functions of plasmoids roughly follow inverse square power laws at large scales. The mass distribution function is steep at large scales and shallow at small scales. The size distribution also shows that plasmoids are highly asymmetric soon after being formed, while older plasmoids tend to be more circular. The spectral profiles of magnetic and kinetic energy inside the current sheet are both consistent with a power law. The corresponding spectral indices γ are found to vary with the magnetic Reynolds number R{sub m} of the system, but tend to approach a constant for large R{sub m} (>10{sup 5}). The motion and growth of blobs change the spectral index. The growth of new islands causes the power spectrum to steepen, but it becomes shallower when old and large plasmoids leave the computational domain.

• OSTI ID: 22227933
• Journal Information: Physics of Plasmas, Vol. 20, Issue 7; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTROPHYSICS
DISTRIBUTION FUNCTIONS
ELECTRIC CURRENTS
FINE STRUCTURE
INDEXES
KINETIC ENERGY
MAGNETIC ISLANDS
MAGNETIC RECONNECTION
MAGNETIC REYNOLDS NUMBER
MAGNETISM
MASS DISTRIBUTION
PLASMA
PLASMA SHEET
PLASMA SIMULATION
PLASMOIDS
SOLAR FLARES
TWO-DIMENSIONAL CALCULATIONS