Global mode of Pi2 waves in the equatorial region - Difference of Pi2 mode between high and equatorial latitudes.

Fluxgate magnetometers with accurate timing data logger were set up at two equatorial stations (Garoua/Maroua and Huancayo), and also at a middle latitude station (Kuju). The phase of Pi2 waves is compared among these stations. It is found that1) Pi2 pulsations in low and equatorial latitudes are linearly polarized approximately along the magnetic meridian, 2) phase difference of the H component of Pi2 waves at different stations is much less than 1/10 of the pulsation period despite a large longitudinal separation (-90°) of the stations, showing the so-called azimuthal wave number, m, to be much less than unity and3) phase difference of the D component at different stations is variable.