Magnetic field rotation at the dayside magnetopause: AMPTE/IRM observations
Magnetic field rotation at the dayside magnetopause: AMPTE/IRM observations
复制标题
日侧磁层顶的磁场旋转：AMPTE/IRM 观测
DOI：
10.1029/97ja03711
复制
发表时间：
1998
期刊：
影响因子：
--
通讯作者：
M. Roth
中科院分区：
文献类型：
--
作者：
J. Keyser;M. Roth
考虑到磁层周围的大尺度磁鞘流模式，De凯瑟和Roth的切向不连续磁层顶模型预测，对于指定的磁场旋转角度和旋转方向，在向阳侧磁层顶表面上平衡是可能的，而在向阳侧磁层顶表面上不可能。在本文中，我们验证这些预测使用5秒的时间分辨率磁场和等离子体观测的低纬度昼侧磁层边界的活动磁层粒子示踪剂探测器/离子释放模块卫星。该模型被证实（1）在赤道以北的黎明交叉点之间存在着大的正磁场旋转，（2）在驻点附近和黄昏处观察到的正和负旋转，（3）低磁剪切黎明交叉点的罕见发生和可疑的切向不连续性。黎明侧低切变交叉处切向不连续平衡的缺乏与文献报道的向北磁鞘场黎明侧低纬边界层厚度增加的观测结果一致。
Given the large-scale magnetosheath flow pattern around the magnetosphere, the tangential discontinuity magnetopause model of De Keyser and Roth predicts, for a prescribed magnetic field rotation angle and rotation sense, where equilibrium is possible on the dayside magnetopause surface and where it is not. In this paper we verify these predictions using 5 s time resolution magnetic field and plasma observations of the low-latitude dayside magnetospheric boundary acquired by the Active Magnetospheric Particle Tracer Explorers/Ion Release Module satellite. The model is confirmed by (1) the dominant presence of large positive magnetic field rotations among the dawnside crossings north of the equator, (2) the observation of positive and negative rotations near the stagnation point and at the duskside, and (3) the rare occurrence and questionable tangential discontinuity nature of low magnetic shear dawnside crossings. The absence of tangential discontinuity equilibrium in dawnside low shear crossings is consistent with the observation of increased dawnside low-latitude boundary layer thickness for northward magnetosheath field reported in the literature.