Magnetospheric turbulence and characteristics of main magnetospheric domains, 26th IUGGтезисы доклада

Дата последнего поиска статьи во внешних источниках: 20 апреля 2016 г.

Работа с тезисами доклада


[1] Magnetospheric turbulence and characteristics of main magnetospheric domains, 26th iugg / E. Antonova, M. Stepanova, J. A. Valdivia et al. // 26th General Assembly of the International Union of Geodesy and Geophysics Scientific programme. — iugg2015prague.com Prague, 2015. — P. ID IUGG–0976. Multiple results of observations demonstrate the existence of high level of turbulence in the magnetospheath, low energy boundary layer and plasma sheet of the magnetosphere of the Earth. The turbulence appear as the consequence of turbulent solar wind flow with high values of Reynolds numbers. Main properties of observed turbulence is its intermittency. Turbulence in magnetosheath leads to great changes of the magnetic field direction near the magnetopause in comparison with its direction before the bow shock including the change of sign of Bz component in ∼30% of cases. Turbulent flows in the plasma sheet involve large scale (with scales ∼1Re) structures including vortexes, thin current sheets, dipolarization fronts, bursty bulk flows (BBF) and others. Pronounced disturbances are observed much more frequently than the substorm onset which is a difficulty of identification of the real reason of the substorm onset. Eddy diffusion coefficient is one of the characteristics of plasma sheet turbulence. We compare the results of observations of eddy diffusion coefficient obtained using data of Geotail, CLUSTER and THEMIS projects. We demonstrate the coincidence of such results with the predictions of the model of quasiequilibrium turbulent plasma sheet. It is ordinarily suggested that auroral oval is the result of plasma sheet mapping to the ionospheric alititudes. Such suggestion contradicts to the results of observations of plasma sheet turbulence. However comparison of the distribution of plasma pressure at the equatorial plane and at low altitudes shows that the main part of the auroral oval does not mapped to the plasma sheet. It is mapped to the surrounding the Earth plasma ring. We discuss the consequences of obtained results for the space weather predictions.

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