Investigation of the strong turbulence in the geospace environment

[摘要] Plasma vortices are often detected by spacecraft in the geospace (atmosphere,ionosphere, magnetosphere) environment, for instance in the magnetosheath andin the magnetotail region. Large scale vortices may correspond to theinjection scale of turbulence, so that understanding their origin isimportant for understanding the energy transfer processes in the geospaceenvironment. In a recent work, turbulent state of plasma medium (especially,ionosphere) is overviewed. Experimental observation data from THEMIS mission(Keiling et al., 2009) is investigated and numerical simulations are carriedout. By analyzing the THEMIS data for that event, we find that severalvortices in the magnetotail are detected together with the main one and thesevortices constitute a vortex chain. Such vortices can cause the strongturbulent state in the different media. The strong magnetic turbulence isinvestigated in the ionsophere as an ensemble of such strongly localized(weakly interacting) vortices. Characteristics of power spectral densitiesare estimated for the observed and analytical stationary dipole structures.These characteristics give good description of the vortex structures.

[学科分类] 电子、光学、磁材料