Role of the pressure force in the explosive dynamics of magnetic islands in double tearing modes

M. Janvier, A. Ishizawa, J. Li, Y. Kishimoto

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    4 Citations (Scopus)

    Abstract

    The evolution of magnetic islands at two resonant surfaces during the development of a global tearing mode is investigated via numerical simulations of a reduced set of magneto-hydrodynamic equations in slab plasmas. The explosive dynamics of the islands resulting in an interchange follows a Rutherford-like regime, also referred to as a weakly coupled double tearing mode. It is found that the latent mechanism of this dynamics is the reduction of the total pressure around the opposite X-point and the abrupt growth is associated with an imbalance of the pressure around the islands. Once this imbalance is well established, each plasmoid is pushed to the opposite X-point, increasing the drive for the field merging. A feedback loop then takes place as the reconnection itself decreases the strength of the magnetic field between the tearing layers, i.e., reinforces the pressure imbalance. This loop accelerates reconnection, thus leading to the observed explosive growth.

    Original languageEnglish
    Article number102112
    Number of pages7
    JournalPhysics of Plasmas
    Volume18
    Issue number10
    DOIs
    Publication statusPublished - Oct 2011

    Keywords

    • plasma magnetohydrodynamics
    • feedback
    • SHEAR PLASMAS
    • plasma pressure
    • tearing instability
    • RECONNECTION
    • explosions
    • MECHANISM
    • numerical analysis
    • GROWTH
    • plasma simulation

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