| A survey of ten years of CANOPUS magnetometer data yielded 3334 Pc5 pulsations. Almost all of these pulsations occurred in two localized regions centered at 08:00 and 16:00 MLT. Fewer occurred in the post-noon region than in the pre-noon region, and all occurred at auroral latitudes. Pre-noon occurrence was found to depend on solar wind proton density, flow speed, and IMF Bz, while post-noon occurrence was independent of these solar wind parameters. Polarization and propagation characteristics indicated an anti-sunward propagation pattern with a polarization reversal across noon, consistent with anti-sunward propagating source disturbances on the magnetopause. Additional pre-/post-noon asymmetries provided strong evidence that the sources of the pulsations are cavity modes and Kelvin-Helmholtz instabilities in the post- and pre-noon regions, respectively. |
