Space Plasma Transport by Kinetic Alfven Waves

点击翻译按钮获取中文摘要

This project will asses the ability of the kinetic Alfven waves to transport shocked solar wind (magnetosheath) plasmas across the outer boundary of the Earth's magnetic field (magnetosphere) known as the magnetopause. Classically this boundary should be impenetrable with magnetosheath plasma penetrating not more than a gyro-radius into the Earth's magnetosphere. However in-situ observations show penetration over widths of 10s of gyro-radii and indeed much of the plasma of the Earth's magnetosphere is populated by magnetosheath plasmas. Significantly, the boundary layer at the magnetopause where magnetosheath and magnetospheric plasma mix is invariably filled with low frequency electromagnetic fluctuations. It has been suggested that these waves are kinetic Alfven waves. Theoretical studies have suggested that kinetic Alfven waves may be effective in transporting plasmas across magnetic fields. This project will use multi-point fields and plasma observations from the Cluster spacecraft at the magnetopause to identify the waves that are present and evaluate their ability to account for plasma transport seen there. Although the project is specifically directed at plasma transport at Earth's magnetopause, the problem is central to plasma transport in many physical situations, including in magnetic loops on the sun and plasma transport in tokomaks and other laboratory plasma devices. The results from the research will be incorporated into a series of workshops designed to introduce K-12 teachers to the physics of Earth's space environment.