Estimation of temporal evolution of the helium plasmasphere based on a sequence of IMAGE/EUV images
Estimation of temporal evolution of the helium plasmasphere based on a sequence of IMAGE/EUV images
复制标题
基于一系列 IMAGE/EUV 图像估计氦等离子体层的时间演化
DOI：
10.1002/2013ja019734
复制
发表时间：
2014
影响因子：
--
通讯作者：
and T. Higuchi
中科院分区：
文献类型：
--
作者：
S. Nakano;M.-C. Fok;P. C. Brandt;and T. Higuchi
我们已经开发了一种技术，用于估计的等离子体层氦离子密度的时间演变的基础上从IMAGE卫星获得的一系列极紫外（EUV）数据。在所提出的技术中，通过使用基于集合变换卡尔曼滤波器的数据同化方法将来自IMAGE的EUV图像合并到等离子体质谱仪的二维流体模型中来获得估计。由于氦等离子体层的运动和空间结构受到内磁层电场的强烈控制，因此也可以使用系综变换卡尔曼滤波器来估计等离子体层顶周围的电场。我们使用在一定条件下从相同数值模型生成的合成图像进行了实验。经确认，成功再现了生成合成图像的条件。我们还提出了一些结果，使用真实的EUV成像数据。最后，我们讨论的可能性估计的密度分布沿着磁场线。由于IMAGE卫星的运动，每个EUV图像都是从不同的方向拍摄的，因此我们可以通过组合多个图像来获得沿着场线的密度分布信息。
We have developed a technique for estimating the temporal evolution of the plasmaspheric helium ion density based on a sequence of extreme ultraviolet (EUV) data obtained from the IMAGE satellite. In the proposed technique, the estimation is obtained by incorporating EUV images from IMAGE into a two‐dimensional fluid model of the plasmasphere using a data assimilation approach based on the ensemble transform Kalman filter. Since the motion and the spatial structure of the helium plasmasphere is strongly controlled by the electric field in the inner magnetosphere, the electric field around the plasmapause can also be estimated using the ensemble transform Kalman filter. We performed an experiment using synthetic images that were generated from the same numerical model under a certain condition. It was confirmed that the condition that generated the synthetic images was successfully reproduced. We also present some results obtained using real EUV imaging data. Finally, we discuss the possibility of estimating the density profile along a magnetic field line. Since each EUV image was taken from a different direction due to the motion of the IMAGE satellite, we could obtain the information on the density profile along a field line by combining multiple images.