Mapping the Auroral Oval into the Magnetotail Using Dynamics Explorer Plasma Data
Mapping the Auroral Oval into the Magnetotail Using Dynamics Explorer Plasma Data
复制标题
使用 Dynamics Explorer 等离子体数据将极光椭圆形映射到磁尾
DOI：
10.5636/jgg.44.1121
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
G. Lu
中科院分区：
文献类型：
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作者：
L. Weiss;P. Reiff;R. Hilmer;J. Winningham;G. Lu
使用 DE-1 和 -2 等离子体数据结合 Tsyganenko '89 和 Hilmer-Voigt'91 磁场模型研究了夜侧极光椭圆形到磁尾的映射。为了阐明磁层区域与 BPS 和 CPS 之间的关系，来自低空等离子体仪器 (LAPI) 的数据被用来确定极冠边界的不变纬度、离散极光的极地边缘、离散-漫射 (BPS/CPS) 极光边界和漫射极光的赤道边缘。当这些场线被追踪到磁尾时，两个模型都表明离散极光（BPS）区域映射到等离子体片主要部分的扩展区域（宽度通常>20 RE），在偶极性更强的内部等离子体片（CPS）之外。由于 BPS 场线映射到如此广泛的中性片穿越距离，我们提出了一个不太令人困惑且更具描述性的术语，其中术语“BPS”分为两个区域：等离子体片边界层（PSBL）和“IPS”，用于各向同性（边界）等离子体片。通过使用高空等离子体仪器（HAPI）的数据来进一步检查极光区磁尾拓扑，以确定电子数密度和温度值极光区间隔 1°。相应的场线被追踪到磁尾至 -15RE 的距离，并与 HUANG 和 FRANK (1986) 的低和中活动水平的磁尾 (10-25RE) 平均等离子体片离子密度和温度进行比较。我们发现 DE-1 高度映射的密度和温度测量值与中尾测量的密度和温度测量值之间存在非常好的对应关系，这表明两个模型都成功地再现了该距离的平均磁层配置。用 Hilmer-Voigt 模型绘制的离子温度平均值略高于 ISEE 数据报告的离子温度平均值，表明该模型可能稍微过度拉伸。在 DE-1 处可以观察到较热的环流和较冷、较新鲜的等离子体片之间有一个显着的重叠区域（5-7 RE 之间）；这些较热的电子具有如此大的各向异性（具有俘获薄饼分布），以至于在 DE-2 的 1000 公里高度上无法观测到它们。
The mapping of the nightside auroral oval into the magnetotail is investigated using DE-1 and -2 plasma data in combination with the Tsyganenko '89 and the Hilmer-Voigt'91 magnetic field models. In an attempt to clarify the relationship between magnetospheric regions and the BPS and CPS, data from the Low Altitude Plasma Instrument (LAPI) are used to determine the invariant latitude of the polar cap boundary, the poleward edge of the discrete aurora, the discrete-diffuse (BPS/CPS) auroral boundary, and the equatorward edge of the diffuse aurora. When these field lines are traced into the magnetotail, both models indicate that the region of discrete aurora (BPS) maps to an extended region (usually>20 RE in width) of the main portion of the plasma sheet outside the more dipolar, inner plasma sheet (CPS). Since BPS field lines map to such a wide range of neutral sheet crossing distances, we propose a less confusing and more descriptive terminology in which the term “BPS” is divided into two regions: the Plasma Sheet Boundary Layer (PSBL) and the “IPS”, for Isotropic (Boundary) Plasma Sheet.Auroral zone-magnetotail topology is further examined by using data from the High Altitude Plasma Instrument (HAPI) to determine values of electron number density and temperatures at 1° intervals across the auroral zone. The corresponding field lines are traced into the magnetotail to a distance of-15RE and compared with magnetotail (10-25RE) mean plasma sheet ion densities and temperatures for low- and mid-activity levels from HUANG and FRANK (1986). We find a very good correspondence between the density and temperature measurements mapped from DE-1 altitudes and those measured in the mid-tail, suggesting that both models successfully reproduce the average magnetospheric configuration at this distance. The mean of the ion temperatures mapped with the Hilmer-Voigt model were slightly higher than those reported from the ISEE data, indicating that the model may be slightly too stretched. A significant region (between-5-7 RE) of overlap between the hotter ring current and the cooler, fresher plasma sheet is observable at DE-1; these hotter electrons are so anisotropic (with a trapped pancake distribution) that they are not observable at the 1000km altitude of DE-2.