Тип публикации: доклад, тезисы доклада, статья из сборника материалов конференций
Конференция: PROBLEMS OF GEOCOSMOS; Saint-Petersburg; Saint-Petersburg
Год издания: 2016
Ключевые слова: magnetosphere, current sheet, flapping waves, kink mode, sausage mode
Аннотация: We study eigenmodes of the MHD waves propagating along the magnetotail current sheet in direction perpendicular to the magnetic field. Wave frequency is proportional to the square root of the product of the magnetic field gradients corresponding to the neutral line. These gradients are the normal and tangential gradients of the tanПоказать полностьюgential and normal magnetic field components, respectively. As a background we consider analytical solution for 2D steady state magnetic field configuration, characterized by a non-symmetric magnetic field profiles across the current sheet. A deviation of the magnetic field profile from the symmetric one is determined by the special parameter. Varying this parameter, we analyzed an influence of the current sheet asymmetry on the wave oscillations. In symmetric case, the wave oscillations can be kink type or sausage type modes, which are independent from each other. But in case of asymmetry a pure kink-type or sausage type wave do not exist. In such case, each eigenmode becomes a mixture of the sausage and kink oscillation. Wave frequencies as functions of wave number are determined for symmetric and asymmetric current sheets. An asymmetry of the current sheet is a destabilizing factor. An increase of the asymmetry parameter leads to increase of the growth rates of the unstable eigenmodes.
Номера страниц: 213-220
Издатель: ООО "Издательство ВВМ"