Empirical model of the Earth's cusp at low-altitudes
The Earth's cusp is a critical "window" for the solar wind plasma to enterthe low-altitude magnetosphere and ionosphere. However, the overall configuration of cusp has not been established. Based on the simulation of two successive substorms on 8 March 2008, we propose a 2D model of l...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | zho |
| Published: |
Editorial Office of Reviews of Geophysics and Planetary Physics
2023-07-01
|
| Series: | 地球与行星物理论评 |
| Subjects: | |
| Online Access: | https://www.sjdz.org.cn/en/article/doi/10.19975/j.dqyxx.2022-044 |
| _version_ | 1827978562673573888 |
|---|---|
| author | Ziqian Liu Hui Li Chi Wang Jinpeng Han Jiangyan Wang |
| author_facet | Ziqian Liu Hui Li Chi Wang Jinpeng Han Jiangyan Wang |
| author_sort | Ziqian Liu |
| collection | DOAJ |
| description | The Earth's cusp is a critical "window" for the solar wind plasma to enterthe low-altitude magnetosphere and ionosphere. However, the overall configuration of cusp has not been established. Based on the simulation of two successive substorms on 8 March 2008, we propose a 2D model of low-altitude (1.1 RE) cusp modulated by the interplanetary magnetic field (IMF) BY and BZ. This model is constructed from curve fitting of low-altitude cusp with an elliptic function controlled by the cusp center and width, which is dependent on IMF BY and BZ. The plasma thermal pressure PT derived from the simulation data is used to extract the cusp center on the sphere surface with a radius of 6 RE. The cusp center is defined as where PT reaches the maximum, and the cusp boundary is identified as where PT decreases to 68% of that at the cusp center. After the high-altitude cusp has been determined, the low-altitude (0.1 RE altitude in the ionosphere) cusp can be obtained from mapping the high-altitude cusp along the magnetic field lines. The coordinate system of the low-altitude cusp used throughout this paper is the magnetic coordinate. The low-altitude cusp extracted from simulations is fitted with the elliptic function controlled by cusp location and width. The cusp geomagnetic latitude (MLAT) increases gradually with northward IMF BZ but decreases significantly with southward IMF BZ. The local magnetic time (MLT) is nearly 12 when BY = 0, corresponding to the observation results. When IMF BY is duskward (dawnward), the cusp center will locate at the post-noon (pre-noon) sector in the northern hemisphere. The MLAT width decreases as IMF BZ swings from north to south, and the MLT width is the opposite. This model is validated by comparing with observations from DMSP satellites during this concerning time interval. Based on this 2D model of low-altitude cusp, the 3D cusp could be obtained further, which would help to space weather prediction. |
| first_indexed | 2024-04-09T21:23:55Z |
| format | Article |
| id | doaj.art-88965b8e5a4d43d2964b5dc5dde2b10a |
| institution | Directory Open Access Journal |
| issn | 2097-1893 |
| language | zho |
| last_indexed | 2024-04-09T21:23:55Z |
| publishDate | 2023-07-01 |
| publisher | Editorial Office of Reviews of Geophysics and Planetary Physics |
| record_format | Article |
| series | 地球与行星物理论评 |
| spelling | doaj.art-88965b8e5a4d43d2964b5dc5dde2b10a2023-03-28T02:41:26ZzhoEditorial Office of Reviews of Geophysics and Planetary Physics地球与行星物理论评2097-18932023-07-0154446647510.19975/j.dqyxx.2022-0442022-044Empirical model of the Earth's cusp at low-altitudesZiqian Liu0Hui Li1Chi Wang2Jinpeng Han3Jiangyan Wang4State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, ChinaState Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, ChinaState Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, ChinaChina Academy of Launch Vehicle Technology, Beijing 100076, ChinaState Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, ChinaThe Earth's cusp is a critical "window" for the solar wind plasma to enterthe low-altitude magnetosphere and ionosphere. However, the overall configuration of cusp has not been established. Based on the simulation of two successive substorms on 8 March 2008, we propose a 2D model of low-altitude (1.1 RE) cusp modulated by the interplanetary magnetic field (IMF) BY and BZ. This model is constructed from curve fitting of low-altitude cusp with an elliptic function controlled by the cusp center and width, which is dependent on IMF BY and BZ. The plasma thermal pressure PT derived from the simulation data is used to extract the cusp center on the sphere surface with a radius of 6 RE. The cusp center is defined as where PT reaches the maximum, and the cusp boundary is identified as where PT decreases to 68% of that at the cusp center. After the high-altitude cusp has been determined, the low-altitude (0.1 RE altitude in the ionosphere) cusp can be obtained from mapping the high-altitude cusp along the magnetic field lines. The coordinate system of the low-altitude cusp used throughout this paper is the magnetic coordinate. The low-altitude cusp extracted from simulations is fitted with the elliptic function controlled by cusp location and width. The cusp geomagnetic latitude (MLAT) increases gradually with northward IMF BZ but decreases significantly with southward IMF BZ. The local magnetic time (MLT) is nearly 12 when BY = 0, corresponding to the observation results. When IMF BY is duskward (dawnward), the cusp center will locate at the post-noon (pre-noon) sector in the northern hemisphere. The MLAT width decreases as IMF BZ swings from north to south, and the MLT width is the opposite. This model is validated by comparing with observations from DMSP satellites during this concerning time interval. Based on this 2D model of low-altitude cusp, the 3D cusp could be obtained further, which would help to space weather prediction.https://www.sjdz.org.cn/en/article/doi/10.19975/j.dqyxx.2022-044cuspempirical modelsolar windmhd simulation |
| spellingShingle | Ziqian Liu Hui Li Chi Wang Jinpeng Han Jiangyan Wang Empirical model of the Earth's cusp at low-altitudes 地球与行星物理论评 cusp empirical model solar wind mhd simulation |
| title | Empirical model of the Earth's cusp at low-altitudes |
| title_full | Empirical model of the Earth's cusp at low-altitudes |
| title_fullStr | Empirical model of the Earth's cusp at low-altitudes |
| title_full_unstemmed | Empirical model of the Earth's cusp at low-altitudes |
| title_short | Empirical model of the Earth's cusp at low-altitudes |
| title_sort | empirical model of the earth s cusp at low altitudes |
| topic | cusp empirical model solar wind mhd simulation |
| url | https://www.sjdz.org.cn/en/article/doi/10.19975/j.dqyxx.2022-044 |
| work_keys_str_mv | AT ziqianliu empiricalmodeloftheearthscuspatlowaltitudes AT huili empiricalmodeloftheearthscuspatlowaltitudes AT chiwang empiricalmodeloftheearthscuspatlowaltitudes AT jinpenghan empiricalmodeloftheearthscuspatlowaltitudes AT jiangyanwang empiricalmodeloftheearthscuspatlowaltitudes |