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.
Журнал: GEOPHYSICAL RESEARCH LETTERS
Выпуск журнала: Vol. 35, Is. 2
ISSN журнала: 00948276
Место издания: WASHINGTON
Издатель: AMER GEOPHYSICAL UNION