Тип публикации: статья из журнала
Год издания: 2015
Идентификатор DOI: 10.1016/j.asr.2015.07.023
Ключевые слова: Magnetosphere, Current sheet, Asymmetry, Oscillations, Aerospace engineering, Space research, Current sheets, Dipole tilt angle, Gradient model, Magnetotail current sheet, Potential wells, Total pressure
Аннотация: We study the dependence of the flapping oscillations on the magnetotail current sheet bending, which is caused by the dipole tilt. Observations show that flapping waves propagate from the center of the current sheet to its flanks with a velocity one order of magnitude less than typical Alfven speed. For our analysis we use the doubПоказать полностьюle gradient model (Erkaev et al., 2009) of the flapping oscillations, which predicts a small minimum of the total pressure (gas plus magnetic) across the current layer. It is the depth of the potential well in the total pressure which defines the period and the speed of the flapping waves. Using the extension of the Kan/Manankova equilibriums for the non-zero dipole tilt we investigate the depth of the potential well with respect to the current sheet bending rate. We show that with the growth of the dipole tilt angle the depth of the potential well becomes smaller, the period of the flapping oscillations increases, and oscillations become nonlinear. There exists the critical tilt angle, where the potential well disappears and flapping regime changes from oscillations to instability. (C) 2015 COSPAR. Published by Elsevier Ltd. All rights reserved.
Журнал: ADVANCES IN SPACE RESEARCH
Выпуск журнала: Vol. 56, Is. 8
Номера страниц: 1699-1706
ISSN журнала: 02731177
Место издания: OXFORD
Издатель: ELSEVIER SCI LTD