Characteristics of eastward drifting omega bands in the morning sector of the auroral oval
Characteristics of eastward drifting omega bands in the morning sector of the auroral oval
复制标题
极光椭圆区晨区向东漂移的欧米伽带特征
DOI：
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发表时间：
1983
期刊：
影响因子：
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通讯作者：
Wolfgang Baumjohann
中科院分区：
文献类型：
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作者：
H. Opgenoorth;J. Oksman;K. Kaila;E. Nielsen;Wolfgang Baumjohann
在1979年10月21日/22日夜间记录的凝视雷达和斯堪的纳维亚磁力计、全天相机和里奇计网络，出现了相当规律的极光欧米伽带及其相关的磁场和电场变化。组合的二维数据被用来推导出与极光形式相关的三维水流的真实模型。在模式计算中，粒子降水中观测到的结构是由不均匀的电离层电导率分布解释的。模型电流系统的主要结果特征是一系列东西取向的向上和向下定向磁场对，分别与视觉极光的明亮和黑暗区域有关。地面磁扰动的主要来源是“蜿蜒的”电离层霍尔电流，由向西的背景电喷流和围绕定域场向电流位置周围的圆形霍尔电流涡旋组成。然而，在不同事件期间在地面上观察到的总磁扰似乎强烈地依赖于霍尔与彼得森电导率的比率和电导率分布的不均匀程度。与极光欧米伽带相关的三维电流系统向东漂移，其速度相当于一般南向电背景场中的E×B漂移。然而，并非在任何时候都能找到完全一致的意见。
The STARE radars and the Scandinavian networks of magnetometers, all-sky cameras, and riometers recorded during the night of October 21/22, 1979, the occurrence of a fairly regular sequence of auroral omega bands and associated magnetic and electric field variations. The combined two-dimensional data are used to derive a realistic model for the three-dimensional current flow associated with the auroral forms. In the model calculations the observed structure in the particle precipitation is accounted for by an inhomogeneous ionospheric conductivity distribution. The main resulting feature of the model current system is a sequence of east–west orientated pairs of upward and downward directed field-aligned currents, associated with the bright and dark areas of the visual aurora, respectively. The major source of magnetic disturbances on the ground is a “meandering” ionospheric Hall current, composed of a westward background electrojet and circular Hall current vortices around the locations of the localized field-aligned currents. The total magnetic disturbance observed on the ground during different events appears, however, to be strongly dependent on the Hall to Pedersen conductivity ratio and the degree of inhomogeneity in the conductivity distribution. The three-dimensional current system associated with the auroral omega bands drifts eastward with a velocity comparable to an E×B drift within the general southward directed electric background field. However, complete agreement was not found at all times.