Mapping the whole of auroral regions onto the magnetosphere

点击翻译按钮获取中文摘要

The goal of this project is to present a mapping method which enables us to map the whole of auroral regions onto the magnetosphere. Usual methods of mapping utilize field-line models that are the average of the magnetic field observed in the magnetosphere. This method is not very reliable in mapping high-latitude auroral regions to the magnetotail (>10 Re), since the magnetic field in the magnetotail includes large fluctuations. In this study, we proposed another method for mapping, in which any field-line models are not used. In our method, particle structures are utilized as tracers for mapping auroral regions to the magnetosphere.(1)In 2004, we analyzed the particle data obtained by the Akebono satellite in the auroral regions and by the Geotail satellite in the magnetotail. We found two kinds of particle structures. These structures were identified both in the auroral and magnetospheric regions. It was expected that they can be utilized as tracers for mapping (Paper 1 and 2).(2)On the basis of these results, we proposed a new method of mapping (field-line tracing) in which we utilize the particle structures as tracers. It was shown (in Paper 3 and 4) that this method is applicable also to the case of high-latitude aurora mapping.Thus, we have succeeded in presenting a new method for mapping. However, our method is successful only in mapping auroral regions observed under the geomagnetically quiet condition. More detailed analysis of particle data obtained under active conditions is planned for completing our model. This is the next step in our study.