Supersubstorms and Extremely Intense Geomagnetically Induced Currents in the Subauroral Region
Rajkumar Hajra (Indian Institute of Technology Indore, India)
Indian Institute of Technology Indore, Simrol, Indore 453552, India
Geomagnetically induced currents (GICs) are intense, low-frequency (~0.001-1 Hz) currents flowing in Earth-ground conductor systems owing to rapid changes of the geomagnetic fields (dB/dt > 1 nT s-1). An analysis of the GIC records for ~2 solar cycle period at the Mäntsälä, Finland (57.9° magnetic latitude) gas pipeline will be presented. Simultaneous observations of the solar wind and interplanetary data and global geomagnetic indices will be utilized to identify space weather events associated with GIC > 10 A and > 30 A events. Relative importance of several geoeffective interplanetary features such as interplanetary shock, solar wind plasma parcel, interplanetary magnetic field northward and southward turnings will be discussed with some examples and statistics.