Earth Induction Effect for Pc 5 Pulsations Observed by Unmanned Magnetometer Network Near Syowa Station, Antarctica.

Unmanned magnetometer network observation was carried out near Syowa Station, Antarctica from early spring to summer seasons of 1988. The network consisted of three remote stations, H100 (80 km south of Syowa Station), Skarvsnes (50 km south-west of Syowa Station), and site F22 (20 km east of Syowa Station). From a cross-correlation analysis of Pc 5 events observed during the magnetometer operation, we found an unusual phase characteristics in vertical component of F22-Syowa pair, which can not be interpreted by a Pc 5 incidence for the ground conductivity with horizontally uniform distribution. We carried out a numerical simulation of Pc 5 incidence for the ground conductivity with a local conductivity anomaly, and based on that model calculation, we can infer a possible effect of local earth currents that may appear in the cross-correlation analysis for such a short separation.