Magnetospheric Current Sheets and Boundary Layers

该研究计划涉及地球磁层中薄电流片和等离子体边界层中发生的一些物理过程。 特别强调磁层顶电流层，它形成磁层的外边界并将其与快速流动的太阳风分开，以及包含已穿透磁层顶的太阳风起源等离子体的相邻边界层。 这些边界层通过磁力连接到极光区电离层，从而为太阳风能量从磁层外围传输到电离层并在电离层消散提供了重要的通道。 第二个重点领域是地磁尾部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发挥着重要作用。 在这两个位置，磁场重新连接过程被认为发生并且具有决定性的重要性。 因此，该研究的主要重点是研究磁层顶和磁尾的重连接。 将通过使用航天器数据、分析模型和计算机模拟来检查稳态和非稳态重连。 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，以及它通过场对准电流和相关的场对准电势降与极光电离层的耦合，其中粒子可能被加速到千伏能量。

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.