Characteristics of equatorial Pc3 pulsations

Most Pc3 studies have been done using data from satellites and low-mid-high latitude stations, while Pc3s at equatorial regions have received less attention. The generation and propagation mechanisms of equatorial Pc3 pulsations are not yet well understood. Considering that the Philippines is located in the equatorial region, we studied the characteristics of equatorial Pc3 pulsations in the H component (H) and D component (D) using the data obtained from Circum-pan Pacific Magnetometer Network (CPMN) stations. The results show that equatorial Pc3 amplitudes at Dip latitudes from -0.65° to 6.79° are dependent on local time and season. The dayside Pc3 showed peak amplitude around noontime. Although Pc4 (H) amplitudes at DAV station (Dip latitude = -0.65°) showed the equatorial enhancement, Pc3 (H) amplitudes at DAV did not exhibit such enhancement. Furthermore, DAV´s Pc3 (H) showed a lower correlation with the equatorial conductivity and equatorial electrojet when compared with Pc4 (H). Based on these results, we conclude that the equatorial Pc3 must be from the upstream region.