DIAGNOSING HIGH LATITUDE GEOSPACE DYNAMICS WITH GROUND MAGNETOMETER ARRAYS
Seminars
Semester 2
For nearly two centuries, geomagnetic observatories have provided essential records of Earth’s magnetic field, offering the earliest evidence of solar activity’s influence on geospace. Today, ground magnetometer arrays extend this legacy, serving as powerful tools to observe geospace dynamics. Magnetic fields act as the primary mediator of energy coupling between the solar wind and the planetary space environment, with the Dungey cycle offering a fundamental framework: solar wind energy is converted into magnetic energy through dayside reconnection, stored in the magnetotail, and subsequently released through nightside reconnection. These processes couple to the ionosphere through currents and waves, producing distinct geomagnetic signatures that serve as ground-based proxies for magnetospheric reconfiguration. Understanding how the magnetosphere–ionosphere coupling system operates and generates such ground signatures has long been a central focus of the community. In our study, preliminary analysis of long-timescale disturbances at very high latitudes reveals unusually clear poleward propagation patterns resembling interplanetary magnetic fields variations.
We propose that these signals provide direct ground-based evidence of the ionospheric footprint of the Dungey cycle. These observations refine our understanding of solar
wind–magnetosphere–ionosphere energy coupling in planetary space environments.
Additional information: Mr. YU Yuan, u3011625@connect.hku.hk