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Ground-Based Observations of Pc 3-4 Magnetic Pulsations

The observations in mid-latitudes are consistent with those in high latitudes. The ground-based geomagnetic observations from mid-latitude stations show that the magnetosphere was much quieter on May 11 than on May 14. The data from three stations in IGPP/LANL magnetometer array are shown in Figure 4 including Air Force Academy site (AFA, MLat: 48.1$\deg$ N) in Colorado, Los Alamos site (LAL, Mlat: 44.6$\deg$ N) in New Mexico, and San Gabriel Dam site (SGD, 40.7$\deg$ N) in California. Local noon is at $\sim$ 19 UT at AFA and LAL and $\sim$ 20 UT at SGD. On May 14, there was enhanced power in Pc 3-4 band throughout the dayside hours at all three stations. As expected, the wave power was strongest at the higher latitude station AFA. However, Pc 3-4 waves were completely absent at the two lower latitude stations, LAL and SGD, on May 11. At AFA, some isolated pulses of Pc 3-4 waves are present in the dayside but the wave power was much smaller in comparison with those on May 14.


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Next: Summary Up: Magnetosphere on May 11, Previous: Polar Observations of Pc

2000 by American Geophysical Union