第23和24太阳活动周高纬地磁感应电流分布特性

Based on the data of the Geomagnetic Induced Currents (GIC, IGIC) in the natural gas transmission pipelines in the high-latitude Mantsala area, Finland, from 1999 to 2017 during the recent two solar cycles. The distribution characteristics of GIC disturbances and the relationship between strong GIC disturbances and magnetic storms and substorms are analyzed. It is found that for 95.83% of the data points, the GIC intensity was distributed between 0 A and 1 A. The occurrence probability of GIC disturbance defined as |/Gic|max > 1 A, is highest near the nightside in MLT, which is possibly related to the stronger ionosphere current disturbances during the magnetospheric substorm at the nightside. All the intense GIC disturbances defined as the events with |/Gic|max > 10A are accompanied by geomagnetic storms. Strong GIC disturbance events mainly occur in the main phase and the recovery phase of the magnetic storms, which are driven by ring current enhancement and have a longer time-duration and greater intensity. On the other hand, there are also a few events with a much shorter duration occurring with the storm sudden commencement. These events are caused by the sudden compression of the magnetosphere.