Propagation Characteristics of Pc1 Waves near the Plasmaspause
Abstract
Previous studies of electromagnetic ion cyclotron waves by satellite missions in the middle magnetosphere have identified an equatorial source region some 10° width in latitude. Here waves are seen to propagate both parallel and antiparallel to the background geomagnetic field. At latitudes beyond 10° waves propagate unidirectionally down the field line towards the ionosphere. To further investigate the source region and associated propagation properties three typical Pc1 wave events seen by the Cluster satellites near the equatorial plasmapause when passing through perigee (L=4.3) and moving northward closely aligned with the geomagnetic field have been analysed in detail. The wave events on 2 November 2001, 30 March 2002 and 22 November 2003 occurred roughly symmetrically around the magnetic equatorial plane within magnetic latitude range 15 at magnetic local times 0800, 2200 and 0730 hr respectively. The wave events were respectively associated with a moderate storm (Dst=-106nT), a reasonably quiet time and a large storm (Dst=-422nT). Magnetic and electric field wave and plasma data from the four satellites show the waves occur near the plasmapause and propagate away from the equatorial region with low wave normal angles. Additional analysis concentrates on the similarities and differences between the wave properties and propagation characteristics seen at the four satellites in relation to their spatial separation and the local plasma environment, particularly with respect to the plasmapause.
- Publication:
-
38th COSPAR Scientific Assembly
- Pub Date:
- 2010
- Bibcode:
- 2010cosp...38.2045L