Predicting the SYM‐H Index Using the Ring Current Energy Balance Mechanism
Abstract The geomagnetic disturbance index SYM‐H is primarily determined by the total kinetic energy of ring current particles. Therefore, the energy balance mechanism of the ring current can be used to construct an SYM‐H evolution equation for prediction purposes. This study extends a modeling conc...
Saved in:
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2025-03-01
|
| Series: | Space Weather |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2024SW004160 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850206593839267840 |
|---|---|
| author | Lan Ma Yong Ji Chao Shen Gang Zeng Peng E YanYan Yang Shuo Ti Nisar Ahmad |
| author_facet | Lan Ma Yong Ji Chao Shen Gang Zeng Peng E YanYan Yang Shuo Ti Nisar Ahmad |
| author_sort | Lan Ma |
| collection | DOAJ |
| description | Abstract The geomagnetic disturbance index SYM‐H is primarily determined by the total kinetic energy of ring current particles. Therefore, the energy balance mechanism of the ring current can be used to construct an SYM‐H evolution equation for prediction purposes. This study extends a modeling concept developed by Ji et al. (2023), https://doi.org/10.1029/2022ea002560 to establish an algebraic equation for predicting the SYM‐H index based on equilibrium between energy injection and ring current loss. The loss term in the model is determined by a fully connected neural network. The fundamental form of the energy injection function is derived from existing solar wind–magnetosphere energy coupling functions, with its scale factor adjusted as a free‐fitting parameter to optimize the prediction of observations. After being trained on solar wind and SYM‐H observations from 20 magnetic storms, the new model predicts the SYM‐H index well 1 hr and 2 hr in advance, with root mean square errors of 6.7 and 8.9 nT, respectively. These accuracies represent a 7% (1‐hr model) and a 6% (2‐hr model) improvement over the previous model. Furthermore, the scale factors for the solar wind parameters in the energy coupling function determined by the new model can be explained by the previous observations in the magnetic tail current sheet, confirming that the ring current energy primarily originates from the current sheet. The lifetime of the ring current particles, as determined by the neural network, varies with the SYM‐H index. It is approximately 6 hr for the fast recovery phase and more than 10 hr for the slow recovery phase, consistent with the dominant ring current particles changing from oxygen ions to protons during intense storms. |
| format | Article |
| id | doaj-art-8c5ec51a0f314051acb9c5dce61c1911 |
| institution | OA Journals |
| issn | 1542-7390 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | Wiley |
| record_format | Article |
| series | Space Weather |
| spelling | doaj-art-8c5ec51a0f314051acb9c5dce61c19112025-08-20T02:10:46ZengWileySpace Weather1542-73902025-03-01233n/an/a10.1029/2024SW004160Predicting the SYM‐H Index Using the Ring Current Energy Balance MechanismLan Ma0Yong Ji1Chao Shen2Gang Zeng3Peng E4YanYan Yang5Shuo Ti6Nisar Ahmad7School of Science Harbin Institute of Technology (Shenzhen) Shenzhen ChinaSchool of Mathematics and Statistics; Ningxia Key Laboratory of Interdisciplinary Mechanics and Scientific Computing; Ningxia Basic Science Research Center of Mathematics Ningxia University Yinchuan ChinaSchool of Science Harbin Institute of Technology (Shenzhen) Shenzhen ChinaSchool of Mathematics and Physics Jingchu University of Technology Jingmen ChinaNational Key Laboratory of Space Environment and Matter Behaviors Harbin Institute of Technology Harbin ChinaNational Institute of Natural Hazards, Ministry of Emergency Management of China Beijing ChinaState Key Laboratory of Space Weather National Space Science Center Chinese Academy of Sciences Beijing ChinaDepartment of Physics Qilu Institute of Technology Jinan P. R. ChinaAbstract The geomagnetic disturbance index SYM‐H is primarily determined by the total kinetic energy of ring current particles. Therefore, the energy balance mechanism of the ring current can be used to construct an SYM‐H evolution equation for prediction purposes. This study extends a modeling concept developed by Ji et al. (2023), https://doi.org/10.1029/2022ea002560 to establish an algebraic equation for predicting the SYM‐H index based on equilibrium between energy injection and ring current loss. The loss term in the model is determined by a fully connected neural network. The fundamental form of the energy injection function is derived from existing solar wind–magnetosphere energy coupling functions, with its scale factor adjusted as a free‐fitting parameter to optimize the prediction of observations. After being trained on solar wind and SYM‐H observations from 20 magnetic storms, the new model predicts the SYM‐H index well 1 hr and 2 hr in advance, with root mean square errors of 6.7 and 8.9 nT, respectively. These accuracies represent a 7% (1‐hr model) and a 6% (2‐hr model) improvement over the previous model. Furthermore, the scale factors for the solar wind parameters in the energy coupling function determined by the new model can be explained by the previous observations in the magnetic tail current sheet, confirming that the ring current energy primarily originates from the current sheet. The lifetime of the ring current particles, as determined by the neural network, varies with the SYM‐H index. It is approximately 6 hr for the fast recovery phase and more than 10 hr for the slow recovery phase, consistent with the dominant ring current particles changing from oxygen ions to protons during intense storms.https://doi.org/10.1029/2024SW004160SYM‐Hspace weathersolar windgeomagnetic strome |
| spellingShingle | Lan Ma Yong Ji Chao Shen Gang Zeng Peng E YanYan Yang Shuo Ti Nisar Ahmad Predicting the SYM‐H Index Using the Ring Current Energy Balance Mechanism Space Weather SYM‐H space weather solar wind geomagnetic strome |
| title | Predicting the SYM‐H Index Using the Ring Current Energy Balance Mechanism |
| title_full | Predicting the SYM‐H Index Using the Ring Current Energy Balance Mechanism |
| title_fullStr | Predicting the SYM‐H Index Using the Ring Current Energy Balance Mechanism |
| title_full_unstemmed | Predicting the SYM‐H Index Using the Ring Current Energy Balance Mechanism |
| title_short | Predicting the SYM‐H Index Using the Ring Current Energy Balance Mechanism |
| title_sort | predicting the sym h index using the ring current energy balance mechanism |
| topic | SYM‐H space weather solar wind geomagnetic strome |
| url | https://doi.org/10.1029/2024SW004160 |
| work_keys_str_mv | AT lanma predictingthesymhindexusingtheringcurrentenergybalancemechanism AT yongji predictingthesymhindexusingtheringcurrentenergybalancemechanism AT chaoshen predictingthesymhindexusingtheringcurrentenergybalancemechanism AT gangzeng predictingthesymhindexusingtheringcurrentenergybalancemechanism AT penge predictingthesymhindexusingtheringcurrentenergybalancemechanism AT yanyanyang predictingthesymhindexusingtheringcurrentenergybalancemechanism AT shuoti predictingthesymhindexusingtheringcurrentenergybalancemechanism AT nisarahmad predictingthesymhindexusingtheringcurrentenergybalancemechanism |