Well-defined ULF Pc 1 geomagnetic pulsations have been observed simultaneously from a ground array of five search-coil magnetometers in the morning sector of Antarctica on Mar. 23, 2007. Distributed over a very extensive range of geomagnetic latitudes (-62 to -87, spanning ∼2920 km geographically) approximately along a magnetic meridian, the array showed poleward propagation of the Pc 1 waves in the ionospheric waveguide. It is observed that attenuation factors are between ∼8 and 20 dB/1000 km and the polarization sense changes from left-hand to right-hand as the waves are ducted poleward. However, a complex polarization pattern (i.e., change in ellipticity and major axis angle) was seen on the ground, which might be attributed to the array being close to the wave injection region where the superposed effect of incident waves and ducted waves is dominant. A CHAMP satellite conjunction showed a transverse and nearly linearly polarized Pc 1 ULF wave at the altitude of the ducting layer (∼350 km) over a limited latitudinal extent (-53 to -61 ILAT). The polarization analysis performed using the ground data supports the idea that CHAMP detected the wave activity near the wave injection region. The observations are unique in that the ducted waves, seen over an array with unprecedented geomagnetic latitudinal range and positioning along a magnetic meridian (a condition that provides the most efficient ducting), have rarely been measured before.
All Science Journal Classification (ASJC) codes
- Space and Planetary Science