The Solar-Terrestrial Environment Laboratory (STEL), Nagoya University, is carrying out multinationally coordinated magnetic observations along the 210° magnetic meridian from high latitudes, through middle and low latitudes, to the equatorial region, spanning L=9.05-1.03, in cooperation with 14 institutes in Japan, Australia, USA, and Russia during the STEP period of 1990-1997. In this paper, we introduce in detail the project of global magnetic observations along the 210° magnetic meridian, and illustrate preliminary results of power spectrum and cross correlation analysis of low-latitude pulsations at the 6 chain stations installed in 1990.
The results can be summarized as follows: (1) There are two spectral peaks in the Pc 3 range. A shorter-period component in the 10-20sec range exhibits standing field-line resonance behavior around L=1.58, while the longer-period component in the 20-50sec range indicates three different characters, a standing field-line oscillation at L>2.1, a second-harmonic cavity resonance oscillation in the plasmasphere, and propagating-mode waves with phase delays from lower to higher latitudes. (2) An ssc with δH-215nT magnitude at L=1.22 on March 24, 1991, was found to stimulate cavity-mode Pc 3 pulsations with duration <20min and identical 15.5 and 25.3mHz frequencies over the L=1.14-2.13 low-latitude region.