Pi2 pulsations associated with poleward boundary intensifications during the absence of substorms

Pi2 pulsations during the intervals of extremely quiet geomagnetic conditions (Kp = 0+) have been reported by Sutcliffe and Lyons [2002]. These authors observed that several Pi2 bursts occurred simultaneously at high (magnetic latitude = 71° ) and low (42° ) latitudes during the absence of magnetospheric substorms and found that the bursts are strongly correlated with poleward boundary intensifications (PBIs). The authors discussed the correlation between the PBI-associated Pi2 (PBI-Pi2) bursts and enhancements of energetic particle fluxes in the plasma sheet, but they did not focus on the wave properties of the PBI-Pi2 pulsations. In this study we examine whether the PBI-Pi2 pulsations at mid/low latitudes exhibit spatial variations similar to substorm-associated Pi2 pulsations. Using ground-based data from latitudinally and longitudinally extended magnetometer network and spacecraft data in the duskside, we discuss the spatial variation of the frequency, amplitude, phase, and inter-station coherence of the PBI-Pi2 pulsations.