An Investigation of Discontinuities in the Solar Terrestrial Environment

这笔拨款将支持通过计算机模拟对无碰撞等离子体中的切向和旋转不连续进行理论研究。这种不连续是日地环境中常见而重要的结构。一个关键的例子是地球的磁层顶，即地球磁场和太阳磁场之间的边界。模拟将使用包含离子动力学效应（如粘度）的一维和二维混合代码进行。模拟结果将用于得到这些不连续面平衡结构的一维和二维模型。模型的稳定性，其中将包括等离子体速度剪切的可能性，将被检查。这些结果将对等离子体扩散、加热和磁层顶的加速以及太阳风的不连续性产生影响。在整个研究过程中，将使用现场观测来约束模型。这项工作在S/T关系中的重要性涉及从太阳风到磁层的能量流。磁层顶的转变显然对这个过程很重要，它实际上为许多磁层活动提供动力，例如亚暴和极光。

This grant will support a theoretical study of tangential and rotational discontinuities in collisionless plasma by means of computer simulations. Such discontinuities are common and important structures in the solar terrestrial environment. A key example is the earth's magnetopause, the boundary between the terrestrial and solar magnetic fields. The simulations will be performed using one and two dimensional hybrid codes which incorporate ion kinetic effects such as viscosity. The simulation results will be used to obtain one and two dimensional models of the equilibrium structure of these discontinuities. The stability of the models, which will include the possibility of plasma velocity shear, will be examined. The results will have implications for plasma diffusion, heating, and acceleration at the magnetopause and discontinuities in the solar wind. Throughout this study in situ observations will be used to constrain the models. The importance of this work in S/T relations concerns the energy flow form the solar wind to the magnetosphere. the magnetopause transition is clearly important to this process which in effect powers much of the magnetosphere's activity e.g. substorms and aurora.