POLAR OBSERVATIONS OF COHERENT ELECTRIC-FIELD STRUCTURES

The POLAR plasma wave instrument often detects coherent electric field structures in the high altitude polar magnetosphere. The structures a ppear to be positively charged potentials which are found to move both up and down the ambient magnetic field. Typical estimated velocities and parallel scale sizes are the order of 1000 km/s and 100-1000 meter s, respectively. We have observed the structures at radial distances o f 2.02 to 8.5 Re and L shells of 6 - 12+, although the they are likely to occur over a broader range of space than suggested by this initial study. The structures are responsible for some of the the spectral fe atures of broadband electrostatic noise, and are similar to recent GEO TAIL and FAST observations of solitary waves.