Improved method to derive equivalent current systems from global MHD simulations |
| |
| Authors: | JiaoJiao Zhang Chi Wang BinBin Tang |
| |
| Institution: | 1. State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing, 100190, China
2. University of Chinese Academy of Sciences, Beijing, 100049, China
|
| |
| Abstract: | Derivation of equivalent current systems (ECS) from a global magnetospheric magnetohydrodynamics (MHD) model is very useful in studying magnetosphere-ionosphere coupling, ground induction effects, and space weather forecast. In this study we introduce an improved method to derive the ECS from a global MHD model, which takes account of the obliqueness of the magnetic field lines. By comparing the ECS derived from this improved method and the previous method, we find that the main characteristics of the ECS derived from the two methods are generally consistent with each other, but the eastward-westward component of the geomagnetic perturbation calculated from the ECS derived from the improved method is much stronger than that from the previous method. We then compare the geomagnetic perturbation as a function of the interplanetary magnetic field (IMF) clock angle calculated from the ECS derived from both methods with the observations. The comparison indicates that the improved method can improve the performance of the simulation. Furthermore, it is found that the incomplete counterbalance of the geomagnetic effect produced by the ionospheric poloidal current and field-aligned current (FAC) contributes to most of the eastward-westward component of geomagnetic perturbation. |
| |
| Keywords: | equivalent current systems global MHD model improved method |
| 本文献已被 CNKI SpringerLink 等数据库收录！ |
|
