Plasmoid instability in double current sheets

Nemati, M. J.; Wei, L.; Selim, B. I.

doi:10.1063/1.4906052

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Plasmoid instability in double current sheets

Nemati, M. J.·Wei, L.·Selim, B. I.

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Abstract

The linear behavior of plasmoid instability in double current sheet configurations, namely, double plasmoid mode (DPM), is analytically and numerically investigated within the framework of a reduced magnetohydrodynamic model. Analytical analysis shows that if the separation of double current sheets is sufficiently small [κx{sub s}≪κ{sup 2/9}S{sub L}{sup 1/3}], the growth rate of DPMs scales as κ{sup 2/3}S{sub L}{sup 0} in the non-constant-ψ regime, where κ=kL{sub CS}/2 is the wave vector measured by the half length of the system L{sub CS}/2, 2x{sub s} is the separation between two resonant surfaces, and S{sub L}=L{sub CS}V{sub A}/2η is Lundquist number with V{sub A} and η being Alfven velocity and resistivity, respectively. If the separation is very large [κx{sub s}≫κ{sup 2/9}S{sub L}{sup 1/3}], the growth rate scales as κ{sup −2/5}S{sub L}{sup 2/5} in the constant-ψ regime. Furthermore, it is also analytically found that the maximum wave number scales as x{sub s}{sup −9/7}S{sub L}{sup 3/7} at the transition position between these two regimes, and the corresponding maximum growth rate scales as x{sub s}{sup −6/7}S{sub L}{sup 2/7} there. The analytically predicted scalings are verified in some limits through direct numerical calculations.

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70 PLASMA PHYSICS AND FUSION TECHNOLOGY ALFVEN WAVES CONFIGURATION CURRENTS PLASMA INSTABILITY PLASMA SHEET RESONANCE SCALING SURFACES VECTORS

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BibTeX RIS

Nemati, M. J., Wei, L., Selim, B. I.. 2015-01-15. Plasmoid instability in double current sheets. https://doi.org/10.1063/1.4906052

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