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Detailed Reference Information |
Zhu, P., Bhattacharjee, A. and Ma, Z.W. (2004). Finite ky ballooning instability in the near-Earth magnetotail. Journal of Geophysical Research 109: doi: 10.1029/2004JA010505. issn: 0148-0227. |
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Two-dimensional initial value MHD simulations of the linear ideal MHD ballooning instability in the near-Earth magnetotail are presented. The configuration of the magnetotail is modeled by the analytic two-dimensional static equilibrium developed by Voigt. For an intermediate range of plasma ¿ values (~1--100) at the equatorial plane, the Voigt configuration of the near-Earth magnetotail is shown to be unstable to ballooning modes with finite ky. (A similar intermediate range of plasma ¿ was also obtained in the stability analyses of ballooning modes in the infinite ky limit.) Such a ¿ dependence of the instability arises because of the stabilizing effect of plasma compression involved in the ballooning displacement of flux tubes in the high-¿ regime of the magnetotail. The growth rate of the finite ky ballooning instability is found to increase with the wave number ky, approaching a saturated value in the very large ky limit. The thinning of the current sheet is found to enhance the regime of unstable ¿ as well as the growth rate of the linear ballooning instability of the near-Earth magnetotail, suggesting a possible scenario for the substorm trigger. |
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BACKGROUND DATA FILES |
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Abstract |
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Keywords
Magnetospheric Physics, Magnetotail, Magnetospheric Physics, Storms and substorms, Magnetospheric Physics, MHD waves and instabilities, Space Plasma Physics, Numerical simulation studies, Mathematical Geophysics, Modeling, substorm onset, trigger, ballooning instability, finite ky, MHD simulation, magnetotail |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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