Thermal ion composition measurements of the formation of the new outer plasmasphere and double plasmapause during storm recovery phase

Thermal ion composition measurements from several successive dusk sector passes by the DE‐1 satellite show the formation of the new outer plasmasphere and double plasmapause following a sharp decrease in geomagnetic activity. In less than one day after the magnetic activity decrease, the outer plasmasphere formed and consisted of cold, essentially Maxwellian plasma with ion composition and thermal energy characteristics generally similar to those of the inner plasmasphere, albeit at significantly lower densities. There is also evidence that at times the thermal O + density is comparable to the H + density within the plasmasphere.