Аннотация:The interaction between a turbulent plasma flow, such as the solar or stellar wind, and a magnetic field acting as an obstacle is a common phenomenon in space and astrophysical plasmas. The Earth's magnetosphere is formed precisely as a result of this interaction, and there is extensive evidence suggesting that the geomagnetic tail behaves like a turbulent wake behind an obstacle. Unlike an ordinary wake, the geomagnetic tail is divided into a plasma sheet, filled with dense, turbulent plasma, and tail lobes filled with rarefied, quasi-laminar plasma. The interaction between the turbulent plasma sheet and the inner magnetosphere is crucial for understanding key magnetospheric processes such as geomagnetic storms and substorms. Meanwhile, variations in solar wind density, velocity, and the interplanetary magnetic field (IMF) simultaneously affect plasma conditions in both the plasma sheet and the inner magnetosphere, although through different and not yet fully understood mechanisms. In this work, data from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission are used to analyze the influence of the IMF and solar wind dynamic pressure on eddy diffusion within the plasma sheet. Our results indicate that eddy diffusion coefficients increase with a southward orientation of the IMF and can intensify by more than an order of magnitude under high values of the solar wind dynamic pressure. Both of these factors contribute to an increase in the plasma beta parameter within the plasma sheet, leading to a shift of the transition zone between turbulent and quasi-laminar plasmas towards Earth.
