| 英文摘要: | This project addresses compelling questions about the effects of oxygen ions on magnetic reconnection and on the dynamics of Earth's near space environment. Magnetic reconnection is, in effect, the breaking and reconnecting of magnetic field lines with an accompanying explosive release of energy. This energy powers space weather disturbances and contributes in essential ways to the dynamics of the space environment surrounding Earth. The methodology is to combine satellite observations with linked models that in combination are capable of examining the effects of oxygen ions on reconnection in micro scale regions while representing the larger-scale behavior of the Earth's magnetosphere that results. The project has significant broader impacts. In addition to training a graduate student and helping to build the scientific workforce, the investigators plan on participating in a program at the University of New Hampshire that provides research experiences to high school students. The investigation contributes to knowledge of reconnection, which is a universal process and of interest to other scientific fields, such as astrophysics and laboratory plasma physics. Understanding of how mass coupling between the ionosphere and magnetosphere affects reconnection and global system dynamics is essential to building an understanding and predictive capability for space weather, a national priority.
Knowledge of the effects of ion composition on the near-Earth space environment is a critical component of models that simulate the response of the magnetosphere to explosive events on the Sun. These oxygen ions originate in the Earth's upper atmosphere. They gain energy during the solar wind interaction with the magnetosphere and flow outward to populate near-Earth space. Their presence alters the mass density of magnetospheric plasma, the environment for the generation of plasma waves, the convection speed of magnetic field lines, the plasma pressure and the thresholds for plasma instabilities. Evidence suggests that the presence of oxygen ions, through their effects on magnetic reconnection and related dynamical processes, can modulate the interaction between the solar wind and magnetosphere as well as the release of energy in the magnetotail, both major factors in the development of space weather disturbances. |