The source location and beaming of terrestrial continuum radiation
The source location and beaming of terrestrial continuum radiation
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地面连续谱辐射的源位置和波束
DOI：
10.1029/91ja00314
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发表时间：
1991
影响因子：
--
通讯作者：
D. Gurnett
中科院分区：
文献类型：
--
作者：
D. Morgan;D. Gurnett
动力学探测器1号航天器的等离子体波数据被用于研究地球连续辐射的源位置和波束。这项研究表明，辐射通常在磁赤道附近产生，径向距离范围为2.0至4.0 RE。辐射以束宽约100°的宽束向外发射，束宽沿着磁赤道定向。连续辐射出现的总频率为60%，在午夜子午线附近急剧增加，朝晨方向增加。几个案例研究来说明各种特性的连续辐射。观测到的特性，然后与琼斯的无线电窗口模型进行比较。观察到Jones模型未预测的几个特征。这些包括大的纬度不对称性，在赤道的发生和强度的最小值的情况下，更高的频带来自更大和更扩散的源区域的趋势，以及从一个单一的区域出现几个不同的光束。特别是在赤道没有出现最小值和强度，以及从一个源区以截然不同的角度出现辐射束，这些都是反对射电窗口模型的证据。此外，相对于磁赤道平面的波束角的基本方程被发现是一个贫穷的预测所观察到的波束角。反对无线电窗口模型的证据部分地被以下事实所缓解：辐射源可能在空间和频率上延伸，有时来自太阳的辐射会干扰测向。总的来说，这些观测结果意味着无线电窗口模型不能完全解释连续辐射的波束模式。
Plasma wave data from the spacecraft Dynamics Explorer 1 were used to study the source location and beaming of terrestrial continuum radiation. This study shows that the radiation usually is generated near the magnetic equator at radial distances ranging from 2.0 to 4.0 RE. The radiation is beamed outward in a broad beam directed along the magnetic equator with a beam width of about 100°. The overall frequency of occurrence of continuum radiation was found to be 60% with a sharp increase near the midnight meridian, increasing in the dawnward direction. Several case studies are presented to illustrate various characteristics of continuum radiation. The observed characteristics are then compared with the radio window model of Jones. Several characteristics not predicted by Jones' model are observed. These include large latitudinal asymmetries, an absence of a minimum in the occurrence and intensity at the equator, a tendency for higher frequency bands to come from larger and more diffuse source regions, and the emergence of several distinct beams from a single region. In particular the absence of a minimum in the occurrence and intensity at the equator and the emergence of beams of radiation at sharply distinct angles from one source region constitute evidence against the radio window model. Also, the basic equation for the beaming angle with respect to the magnetic equatorial plane is found to be a poor predictor of the observed beaming angle. The evidence against the radio window model is partially mitigated by the facts that the source of radiation is probably extended in space and frequency and that sometimes radiation from the Sun interferes with the direction finding. Overall, these observations imply that the radio window model does not fully explain the beaming pattern of continuum radiation.