Turbulence driven magnetic reconnection causing long-wavelength magnetic islands

Ishizawa, A.; Nakajima, N.
July 2010
Physics of Plasmas;Jul2010, Vol. 17 Issue 7, p072308
Academic Journal
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.


Related Articles

  • The Magnetic Field of the Earth's Lithosphere. Thébault, Erwan; Purucker, Michael; Whaler, Kathryn; Langlais, Benoit; Sabaka, Terence // Space Science Reviews;Aug2010, Vol. 155 Issue 1-4, p95 

    The lithospheric contribution to the Earth's magnetic field is concealed in magnetic field data that have now been measured over several decades from ground to satellite altitudes. The lithospheric field results from the superposition of induced and remanent magnetisations. It therefore brings...

  • Geophysics: A fuel-efficient geodynamo? Holme, Richard // Nature;5/13/2004, Vol. 429 Issue 6988, p137 

    The Earth's magnetic field originates in the core, a fluid region almost 3,000 km below one's feet of which the main constituent is molten iron. The basic mechanism of field generation is generally accepted it is a dynamo process, in which the magnetic field is maintained by convection of the...

  • Modification of a digital elevation model (DEM) in a flat topographic area with respect to manmade features. Kanoua, Wael; Merkel, Broder // Geosciences Journal;Feb2016, Vol. 20 Issue 1, p101 

    This study compares two Digital Elevation Models (DEMs) that are available free of charge: (1) the Consultative Group for International Agriculture Research Consortium for Spatial Information SRTM C-band CGIAR-CSI v4.1 (SRTM): 3 arc sec (approximately 92 m at the equator; originally 1 arc sec...

  • MAGNETIC FIELD AMPLIFICATION BY SN-DRIVEN INTERSTELLAR TURBULENCE. Gressel, O.; Ziegler, U.; Elstner, D. // EAS Publications Series;2010, Vol. 44, p73 

    Supernovae are known to be the dominant energy source for driving turbulence in the interstellar medium. Yet, their effect on magnetic field amplification in spiral galaxies is still poorly understood. Analytical models based on the uncorrelated-ensemble approach predicted that any created field...

  • Reconnection current sheet structure in a turbulent medium. Vishniac, E. T.; Pillsworth, S.; Eyink, G.; Kowal, G.; Lazarian, A.; Murray, S. // Nonlinear Processes in Geophysics;2012, Vol. 19 Issue 6, p605 

    In the presence of turbulence, magnetic field lines lose their dynamical identity and particles entrained on field lines diffuse through space at a rate determined by the amplitude of the turbulence. In previous work (Lazarian and Vishniac, 1999; Kowal et al., 2009; Eyink et al., 2011) we showed...

  • Surface flux concentrations in a spherical α² dynamo. Jabbari, S.; Brandenburg, A.; Kleeorin, N.; Mitra, D.; Rogachevskii, I. // Astronomy & Astrophysics / Astronomie et Astrophysique;Aug2013, Vol. 556 Issue 6, p1 

    Context. In the presence of strong density stratification, turbulence can lead to the large-scale instability of a horizontal magnetic field if its strength is in a suitable range (around a few percent of the turbulent equipartition value). This instability is related to a suppression of the...

  • Fast magnetic reconnection and sudden enhancement of current sheets due to inward boundary flows. Wang, Xiaogang; Ma, Z.W.; Bhattacharjee, A. // Physics of Plasmas;May96, Vol. 3 Issue 5, p2129 

    Magnetic reconnection is widely believed to be involved in dynamical phenomena such as solarflares or magnetospheric substorms. The Sweet?Parker model of magnetic reconnection in a Y-type geometry predicts a characteristic time scale proportional to S1/2 (where S is the Lundquist number), which...

  • The Geophysics of Mercury: Current Status and Anticipated Insights from the MESSENGER Mission. Zuber, Maria T.; Aharonson, Oded; Aurnou, Jonathan M.; Cheng, Andrew F.; Hauck II, Steven A.; Heimpel, Moritz H.; Neumann, Gregory A.; Peale, Stanton J.; Phillips, Roger J.; Smith, David E.; Solomon, Sean C.; Stanley, Sabine // Space Science Reviews;Aug2007, Vol. 131 Issue 1-4, p105 

    Current geophysical knowledge of the planet Mercury is based upon observations from ground-based astronomy and flybys of the Mariner 10 spacecraft, along with theoretical and computational studies. Mercury has the highest uncompressed density of the terrestrial planets and by implication has a...

  • Observations of PC5 pulsations near field-aligned current regions. Alexander Bochev; Karel Kudela; Iren Dimitrova; Petko Nenovski; Ashwini Sinha; Marián Slivka // Studia Geophysica & Geodaetica;Oct2009, Vol. 53 Issue 4, p537 

    Abstract  Examples of long period Pc5 magnetic field pulsations near field-aligned current (FAC) regions in the high-latitude magnetosphere, observed by INTERBALL-Auroral satellite during January 11, April 11 and June 28, 1997 are shown. Identification of corresponding magnetosphere...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics