Table of Contents

Physical backgrounds and origin of the idea.- Concept of the PC index.- Unified procedure for on-line calculation of the 1-min PCN and PCS indices.- Validation of the unified procedure.- Differences in summer and winter PC indices and their physical reasons.- Response of PC index to sudden pulses in the solar wind dynamic pressure.- PC index as an indicator of the substorm development.- PC index as an indicator of the magnetic storm development.- PC index as an input to monitor the disturbances in the polar ionosphere.- Relationship between magnetic activity in the polar cap and atmospheric processes in the winter Antarctica.- Solar wind - magnetosphere coupling in the light of the PC dynamics.