Magnetic double gradient mechanism for flapping oscillations of a current sheet

Описание

Тип публикации: статья из журнала

Год издания: 2008

Идентификатор DOI: 10.1029/2007GL032277

Ключевые слова: Geomagnetism, Magnetic fields, Magnetohydrodynamics, Magnetosphere, Mathematical models, Current sheet, Flapping oscillations, Magnetic double gradient mechanism, Magnetotail, Geophysics, gradient analysis, magnetic field, wave propagation

Аннотация: A new kind of magnetohydrodynamic waves are analyzed for a current sheet in a presence of a small normal magnetic field component varying along the sheet. As a background, two simplified models of a current sheet are considered with a uniform and nonuniform current distributions in the current sheet. On a basis of these two models,Показать полностьюthe flapping-type waves are obtained which are related to a coexistence of two gradients of the tangential and normal magnetic field components along the normal and tangential directions with respect to the current sheet. A stable situation for the current sheet is associated with a positive result of the multiplication of the two magnetic gradients, and unstable ( wave growth) condition corresponds to a negative result of the product. In the stable region, the "kink''-like wave mode is interpreted as so called flapping waves observed in the Earth's magnetotail current sheet.

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Издание

Журнал: GEOPHYSICAL RESEARCH LETTERS

Выпуск журнала: Vol. 35, Is. 2

ISSN журнала: 00948276

Место издания: WASHINGTON

Издатель: AMER GEOPHYSICAL UNION

Персоны

  • Erkaev N.V. (Siberian Federal University)
  • Semenov V.S. (Institute of Physics,State University of St. Petersburg)
  • Biernat H.K. (Institute of Physics,University of Graz)