Magnetospheric Current Sheets and Boundary Layers

拟议的工作是一个正在进行的研究方案的继续，该方案涉及地球磁层薄电流片和等离子体边界层中发生的一些物理过程和结构，特别强调磁层顶。 这个电流片形成了磁层的外边界，并将其与快速流动的太阳风分开。 拟议的研究涉及五个相关的问题领域： 根据航天器数据构建磁场 “横断面”描述磁场内部的覆盖，或 在磁层顶之外，在沿该层沿着移动的细长凸起上方。 其结果将是一个强大的，彻底的基准数据分析工具，可供其他研究人员使用。 应用不仅包括磁层顶上的移动凸起和波，还包括其他移动电流丝，例如，在低纬度边界层或地磁尾。 O 描述中尺度的类似横断面的构建 磁结构，如撕裂模式岛，在磁层顶本身。 同样，目标是开发和测试一个强大的数据分析工具，预计将是有用的和重要的二维结构的磁层顶的研究。 O 弱非线性波脉冲在磁层顶上传播的理论研究及其与当年观测到的沿沿着移动的隆起的关系。 O 对稳定的、二维的、场取向的磁流体流动中的强非线性的理论研究，包括椭圆和双曲线状态之间的转换。 搜索和分析航天器数据中的说明性事件。 O 二维重联层中磁流体流动的理论研究。 在每一个领域，研究将从分析和相关的数值工作开始，包括酌情生成合成航天器数据，以作为数据分析技术的基准;在这一阶段之后，将确定样本事件，并测试航天器数据上的新技术，这些数据最初来自AMPTE/AMPTE，但在项目后期，来自CLUSTER使命。

The proposed work represents continuation of an ongoing research program concerned with some of the physical processes and structures that occur in thin electrical current sheets and plasma boundary layers in the Earth's magnetosphere, with special emphasis on the magnetopause. This current sheet forms the outer boundary of the magnetosphere and separates it from the rapidly streaming solar wind. The proposed research is concerned with five related problem areas: o Construction, from spacecraft data, of magnetic field "transects" describing the draping of magnetic field inside or outside the magnetopause over elongated bulges moving in a transverse sense along that layer. The result will be a robust and thoroughly bench-marked data analysis tool that can be used by other researchers. Applications include, not just traveling bulges and waves on the magnetopause, but other moving current filaments, e.g., in the low latitude boundary layer or in the geomagnetic tail. o Construction of similar transects describing mesoscale magnetic structures, such as tearing mode islands, in the magnetopause itself. Again, the goal is to develop and test a robust data analysis tool that is expected to be of utility and importance for study of two-dimensional structures in the magnetopause. o Theoretical study of weakly nonlinear wave pulses propagating on the magnetopause and their relation to observed bulges moving along that year. o Theoretical study of strong nonlinearities in steady, two- dimensional, field-aligned MHD flows, including transitions between elliptic and hyperbolic states. Search for, and analysis of, illustrative events in spacecraft data. o Theoretical study of MHD flow in two-dimensional reconnection layers. In each area, the research will start with analytical and associated numerical work, including, where appropriate, the generation of synthetic spacecraft data for bench marking of the data analysis techniques; this phase will be followed by identificaion of sample events and by testing of the new techniques on spacecraft data, initially from AMPTE/IRM, but later in the project, from the CLUSTER mission.