...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >Double cusp: Model prediction and observational verification
【24h】

Double cusp: Model prediction and observational verification

机译：双尖峰：模型预测和观测验证

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Recent modeling of the entry of solar wind plasma into the magnetosphere and ionosphere has adequately simulated the large-scale particle precipitation features in the observed cusp, mantle, polar rain, and open-field line low-latitude boundary layer regions. The assumption of a simple dawn-dusk electric field limited the models to the near-noon region and southward interplanetary magnetic field (IMF) case. Here, we present an improved model that incorporates the electric field obtained from statistical convection patterns. When the IMF is strongly duskward/dawnward and weakly southward, the model predicts the occurrence of a double cusp near noon: one cusp at lower latitude and one at higher latitude. The lower-latitude cusp ions originate from low-latitude magnetosheath, whereas the higher-latitude ions originate from the high-latitude magnetosheath. The lower-latitude cusp is located in the region of weak azimuthal E x B drift, resulting in a dispersionless cusp, as would be observed from a typical meridional trajectory of a polar-orbiting satellite. The higher-latitude cusp is located in the region of strong azimuthal and poleward E x B drift. Because of a significant poleward drift, the higher-latitude cusp dispersion has some resemblance to that of the typical southward IMF cusp. This prediction was subsequently confirmed in a large case study with Defense Meteorological Satellite Program (DMSP) data. Occasionally, the two parts of the double cusp have such narrow latitudinal separation that they give the appearance of just one cusp with extended latitudinal width. From the 40 DMSP passes selected during periods of large (positive or negative) IMF B, and small negative IMF B-z, 30 (75%) of the passes exhibit double cusps or cusps with extended latitudinal width. The double-cusp result is consistent with the following new statistical results: (1) the cusp latitudinal width increases with IMF B-y and (2) the cusp equatorward boundary moves to lower latitude with increasing IMF B-y. [References: 79]
机译：太阳风等离子体进入磁层和电离层的最新模型已经充分地模拟了在观测到的尖端，地幔，极地雨和开放场线低纬边界层区域中的大规模颗粒降水特征。简单的黎明黄昏电场的假设将模型限制在近午区域和南向行星际磁场（IMF）的情况下。在这里，我们提出了一种改进的模型，其中包含了从统计对流模式获得的电场。当IMF强烈向黄昏/黎明向南偏弱时，该模型将预测中午附近出现双尖峰：低纬度一个尖峰，高纬度一个尖峰。较低纬度的尖峰离子起源于低纬度的磁荒，而较高纬度的离子起源于高纬度的磁荒。从纬向轨道卫星的典型子午线轨迹可以看到，较低纬度的尖点位于方位角E x B漂移较弱的区域，从而导致无色散的尖点。高纬度的尖点位于强烈的方位角和极移E x B漂移的区域。由于极点向极漂移，较高纬度的尖点散布与典型的向南的IMF尖点相似。这项预测随后在国防气象卫星计划（DMSP）数据的大型案例研究中得到证实。有时，双尖瓣的两个部分具有如此狭窄的纬向间距，以致它们看起来只有一个尖瓣而具有扩展的纬向宽度。在大（正或负）IMF B和小负IMF B-z期间选择的40条DMSP通行证中，有30条（75％）通行证表现出双尖峰或横向宽度扩展的尖峰。双尖峰结果与以下新的统计结果一致：（1）尖峰纬度宽度随 IMF B-y 而增加;（2）尖锐赤道边界随 IMF B-y 向低纬度移动。 [参考：79]

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号