Кл.слова (ненормированные):
Dispersions -- Eigenvalues and eigenfunctions -- Linearization -- Magnetic fields -- Analytical estimates -- Current sheets -- Dispersion relations -- Gradient model -- Growth directions -- Initial perturbation -- Magnetic field components -- Mode dispersion -- Magnetohydrodynamics
Аннотация: Kink-like magnetotail flapping oscillations in a Harris-like current sheet with earthward growing normal magnetic field component Bz are studied by means of time-dependent 2D linearized MHD numerical simulations. The dispersion relation and two-dimensional eigenfunctions are obtained. The results are compared with analytical estimates of the double-gradient model, which are found to be reliable for configurations with small Bz up to values ? 0.05 of the lobe magnetic field. Coupled with previous results, present simulations confirm that the earthward/tailward growth direction of the Bz component acts as a switch between stable/unstable regimes of the flapping mode, while the mode dispersion curve is the same in both cases. It is confirmed that flapping oscillations may be triggered by a simple Gaussian initial perturbation of the Vz velocity. © 2016 Author(s).
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Держатели документа:
Space Research Institute, Austrian Academy of Sciences, 8042 Schmiedlstrasse 6, Graz, Austria
Saint Petersburg State University, Ulyanovskaya 1, Petrodvoretz, Russian Federation
Theoretical Physics Division, Petersburg Nuclear Physics Institute, Gatchina, Russian Federation
Institute of Computational Modelling, Russian Academy of Sciences, Siberian Branch, Krasnoyarsk, Russian Federation
Siberian Federal University, Krasnoyarsk, Russian Federation
Доп.точки доступа:
Korovinskiy, D. B.; Ivanov, I. B.; Semenov, V. S.; Erkaev, N. V.; Kiehas, S. A.