为研究适用于区域电离层总电子含量(total electron content, TEC)建模的方法和估计策略,对传统单层假设下的几种建模方法和估计策略进行了比较分析.基于我国中纬度武汉地区17个连续运行参考站的数据进行TEC建模,建模方法分别采用4...为研究适用于区域电离层总电子含量(total electron content, TEC)建模的方法和估计策略,对传统单层假设下的几种建模方法和估计策略进行了比较分析.基于我国中纬度武汉地区17个连续运行参考站的数据进行TEC建模,建模方法分别采用4×3阶多项式模型、2阶多项式模型、4阶球谐级数模型,估计策略使用分段常数估计策略和分段线性估计策略.在传统单层假设的基础上,本文还提出了三层电离层TEC模型,该模型可以分别给出底部电离层、峰高电离层和顶部电离层的TEC.研究结果表明,几种模型的天顶方向总电子含量拟合效果和欧洲轨道确定中心公布的电离层格网地图均具有较好的一致性,其中4阶球谐级数模型和分段线性估计策略效果最佳.通过三层电离层模型,可以得到TEC与电离层高度之间的关系,多层电离层模型对空间目标监视和低轨卫星航天测控具有重要应用价值.展开更多
The focused transport equation(FTE)contains the necessary physics of shock acceleration but avoids the limitation of small pitch-angle anisotropy inherent in the cosmic ray transport equation.We present a focused tran...The focused transport equation(FTE)contains the necessary physics of shock acceleration but avoids the limitation of small pitch-angle anisotropy inherent in the cosmic ray transport equation.We present a focused transport model based on FTE to investigate the spatial distribution and anisotropy of energetic particles accelerated by shock waves from pickup ions.It is found that in the upstream of the shock,the accelerated particles are highly anisotropic,but in the downstream it is approximately isotropic.An intensity spike is formed across the shock.These simulation results are qualitatively consistent with the observations of the termination shock particles by two Voyager spacecraft in the vicinity of the termination shock.展开更多
文摘为研究适用于区域电离层总电子含量(total electron content, TEC)建模的方法和估计策略,对传统单层假设下的几种建模方法和估计策略进行了比较分析.基于我国中纬度武汉地区17个连续运行参考站的数据进行TEC建模,建模方法分别采用4×3阶多项式模型、2阶多项式模型、4阶球谐级数模型,估计策略使用分段常数估计策略和分段线性估计策略.在传统单层假设的基础上,本文还提出了三层电离层TEC模型,该模型可以分别给出底部电离层、峰高电离层和顶部电离层的TEC.研究结果表明,几种模型的天顶方向总电子含量拟合效果和欧洲轨道确定中心公布的电离层格网地图均具有较好的一致性,其中4阶球谐级数模型和分段线性估计策略效果最佳.通过三层电离层模型,可以得到TEC与电离层高度之间的关系,多层电离层模型对空间目标监视和低轨卫星航天测控具有重要应用价值.
基金Partially supported by the National Basic Research Program of China under Grant No 2012CB825601the Knowledge Innovation Program of the Chinese Academy of Sciences(KZZD-EW-01-4)+1 种基金the National Natural Science Foundation of China(41174152,41231068,41031066,40904048,40904049,41004082,and 41204127)the Specialized Research Fund for State Key Laboratories.
文摘The focused transport equation(FTE)contains the necessary physics of shock acceleration but avoids the limitation of small pitch-angle anisotropy inherent in the cosmic ray transport equation.We present a focused transport model based on FTE to investigate the spatial distribution and anisotropy of energetic particles accelerated by shock waves from pickup ions.It is found that in the upstream of the shock,the accelerated particles are highly anisotropic,but in the downstream it is approximately isotropic.An intensity spike is formed across the shock.These simulation results are qualitatively consistent with the observations of the termination shock particles by two Voyager spacecraft in the vicinity of the termination shock.
