Plasma Sheet of the Magnetosphere of the Earth as the turbulent Wake: Analysis of Properties and Modelingтезисы доклада

Дата последнего поиска статьи во внешних источниках: 28 мая 2015 г.

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[1] Plasma sheet of the magnetosphere of the earth as the turbulent wake: Analysis of properties and modeling / E. E. Antonova, M. Stepanova, J. A. Valdivia et al. // Abstracts of AGU Chapmen Conference on Fundamental Properties and Processes of Magnetotails. — AGU Reykjavik, Iceland, 2013. — P. 14–14. Geomagnetic tail is formed in the process of turbulent solar wind flow around the magnetic field of the Earth. The main difference of the geomagnetic tail in comparison with ordinary turbulent wake under the obstacle is connected with the scales of the turbulent wake. The scale of the turbulent wake in the direction transverse to flow is the same as the scale of the obstacle. The scale of the plasma sheet, which is the region of the turbulent flow in the magnetosphere of the Earth when Bz IMF<0, is the same as the scale of the magnetosphere in Y direction (∼40Re) and much smaller in Z direction (∼5 Re). The theory of the plasma sheet with medium scale turbulence explains these phenomena as the result of the existence of quasistationary dawn-dusk electric field. The theory is based on the suggestion of the existence of a total pressure balance across the plasma sheet and the assumption that the regular plasma transport, which is transverse to the plasma sheet and related to the dawn–dusk electric field, is compensated by the eddy diffusion turbulent transport. The theory predicted the value of eddy diffusion coefficient before it was measured on satellites. It gives the simple explanation of the plasma sheet thinning during substorm growth phase and expansion after start of substorm expansion phase, filling of tail lobes and theta-aurora formation when Bz IMF>0. The results of complex latest studies of magnetosheric turbulence in the tail region using THEMIS, CLUSTER and INTERBALL data are summarized with the aim of the determination of the properties, distribution and dependence on substorm phase of the eddy diffusion coefficient. It is shown, that the level of turbulence is considerably decreased at geocentric distances smaller than 10Re.

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