Magnetospheric Current Sheets and Boundary Layers

这个研究项目关注的是发生在地球磁层薄电流片和等离子体边界层中的一些物理过程。特别强调的是磁层顶电流层，它形成了磁层的外边界，并将其与快速流动的太阳风分开，以及邻近的边界层，其中包含太阳风起源的等离子体，已经穿透了磁层顶。这些边界层与极光区电离层有磁性联系，因此为太阳风能量从磁层的外围传输到电离层提供了一个重要的通道，并在电离层中消散。第二个重点领域是地磁尾中的电流片和邻近的等离子体片边界层，它们在磁暴和亚暴中起着重要作用。在这两个位置，磁场重联过程被认为是主要的。因此，研究的主要重点是研究磁层顶和磁尾的重联。稳定和非稳定重联将通过使用航天器数据、分析建模和计算机模拟进行检查。该项目的第二个重点是研究位于赤道磁层顶内部的低纬度边界层的结构和稳定性，以及它通过场向电流和相关的场向电位下降与极光电离层的耦合，其中粒子可能被加速到千伏特的能量。

This research program is concerned with some of the physical processes that occur in thin electrical current sheets and plasma boundary layers in the Earth's magnetosphere. Special emphasis is placed on the magnetopause current layer, which forms the outer boundary of the magnetosphere and separates it from the rapidly streaming solar wind, and the adjacent boundary layers which contain plasma of solar-wind origin that has penetrated the magnetopause. These boundary layers are magnetically connected to the auroral-zone ionosphere and thus provide an important channel for the transport of solar-wind energy from the outer reaches of the magnetosphere to the ionosphere where it is dissipated. A second area of emphasis is the current sheet in the geomagnetic tail and the adjacent plasma sheet boundary layers which play an important role in magnetic storms and substorms. In both of these locations the magnetic-field reconnection process is believed to occur and to be of dominant importance. For this reason, the primary focus of the research is to study reconnection, both at the magnetopause and in the magnetotail. Steady and nonsteady reconnection will be examined by use of spacecraft data, analytical modeling, and computer simulation. A secondary focus of the project is a study of the structure and stability of the low-latitude boundary layer, located just inside the equatorial magnetopause, and its coupling to the auroral ionosphere via field-aligned currents and associated field-aligned potential drops in which particles may be accelerated to kilovolt energies.