Turbulence driven magnetic reconnection causing long-wavelength magnetic islands

Journal Article · Thu Jul 15 00:00:00 EDT 2010 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3463435· OSTI ID:21389107

Ishizawa, A; Nakajima, N ^[1]

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1. National Institute for Fusion Science, Toki 509-5292 (Japan)

Magnetic reconnection caused by turbulence in a current sheet is studied by means of numerical simulations of fluid equations. It is found that turbulence produces long-wavelength magnetic islands even if the current sheet is so thick that spontaneous magnetic reconnection does not occur. Thus, turbulence modifies the threshold of magnetic island formation predicted by the conventional theory of spontaneous magnetic reconnection in a current sheet. In spite of the fact that the turbulence is driven by a short-wavelength instability due to a pressure gradient, the length of the magnetic island is the same order as the system size. The width of the island is several times the ion Larmor radius, and stronger turbulence causes wider magnetic islands. This suggests that the turbulence can trigger neoclassical tearing modes, which are the main nonlinear instability that limits the plasma pressure in magnetically confined plasmas. The long-wavelength magnetic island is formed by merging of small-scale magnetic islands.

• OSTI ID: 21389107
• Journal Information: Physics of Plasmas, Vol. 17, Issue 7; Other Information: DOI: 10.1063/1.3463435; (c) 2010 American Institute of Physics; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COMPUTERIZED SIMULATION
LARMOR RADIUS
MAGNETIC ISLANDS
MAGNETIC RECONNECTION
MAGNETOHYDRODYNAMICS
PLASMA
PLASMA PRESSURE
PLASMA SIMULATION
PRESSURE GRADIENTS
TEARING INSTABILITY
TURBULENCE
WAVELENGTHS
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
MAGNETIC FIELD CONFIGURATIONS
MECHANICS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
SIMULATION