The importance of ground magnetic data in specifying the state of magnetosphere–ionosphere coupling: a personal view
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- 作者：Y. Kamide ; Nanan Balan
- 关键词：Geomagnetic field ; Magnetic storm and substorm ; Magnetosphere–ionosphere coupling ; Geomagnetic activity indices ; Auroral electrojets ; Magnetogram inversion ; Solar wind ; Loading–unloading process ; Directly driven process
- 刊名：Geoscience Letters
- 出版年：2016
- 出版时间：December 2016
- 年：2016
- 卷：3
- 期：1
- 全文大小：1,984 KB
- 刊物类别：Earth Sciences, general; Atmospheric Sciences; Geophysics/Geodesy; Oceanography; Planetology; Biogeo
- 刊物主题：Earth Sciences, general; Atmospheric Sciences; Geophysics/Geodesy; Oceanography; Planetology; Biogeosciences;
- 出版者：Springer International Publishing
- ISSN：2196-4092
文摘
In the history of geomagnetism, geoelectricity and space science including solar terrestrial physics, ground magnetic records have been demonstrated to be a powerful tool for monitoring the levels of overall geomagnetic activity. For example, the Kp and ap indices having perhaps the long-history geomagnetic indices have and are being used as space weather parameters, where “p” stands for “planetary” implying that these indices express average geomagnetic disturbances on the entire Earth in a planetary scale. To quantify the intensity level of geomagnetic storms, however, it is common to rely on the Dst index, which is supposed to show the magnitude of the storm-time ring current. Efforts were also made to inter-calibrate various activity indices. Different indices were proposed to express different aspects of a phenomenon in the near-Earth space. In the early 1980s, several research groups in Japan, Russia, Europe and the US developed the so-called magnetogram-inversion techniques, which were proposed all independently. Subsequent improvements of the magnetogram-inversion algorithms allowed their technology to be applied to a number of different datasets for magnetospheric convection and substorms. In the present review, we demonstrate how important it was to make full use of ground magnetic data covering a large extent in both latitudinal and longitudinal directions. It is now possible to map a number of electrodynamic parameters in the polar ionosphere on an instantaneous basis. By applying these new inverse methods to a number of ground-based geomagnetic observations, it was found that two basic elements in spatial patterns can be viewed as two physical processes for solar wind-magnetosphere energy coupling.