An indicator of local auroral electrojet peak intensity and latitude inferred from scalar magnetometer measurements made by the Swarm satellites

Auroral electrojets (AEJ) are crucial for understanding the connection between solar wind and the plasma environment near Earth. However, there has been limited research by using peak of AEJ as an index to monitor the auroral activity. In this study, we propose a method by using a single line current (SLC) to determine the magnitude and location of AEJ peak. Ten years of scalar magnetic field data from the Swarm satellite, covering the period from 2013 to 2023, have been analyzed. By comparing our SLC-based AEJ peaks with the Level-2 product of Swarm, AEBS, based on the Line current (LC) method, we found a strong linear relationship between the two peaks, with correlation coefficient of 0.97. Furthermore, the SLC-based peaks of AEJ have been further validated against the ground-based SuperMAG electrojet (SME) index. The results demonstrate also a good correlation between the SLC-based peak of AEJ and the SME index. Compared to the LC approach, which needs complex assumptions about the current distribution, and iterative inversion techniques to estimate the auroral electrojet profile, the SLC method is a much simpler and efficient approach, but can also accurately monitor the spatiotemporal distribution of AEJ.