Temporal variations in slant total plasmasphere content and their relationship to the ring current intensity and the plasmapause


  • D. C. Webb,

  • L. J. Lanzerotti


The time dependence of the total electron content of the plasmasphere, as determined from the radio beacon experiment on the ATS 6 satellite, is studied for an 11-month period in 1974–1975 (Fritz, 1976). Close temporal associations are often observed between increases (decreases) in the ring current intensity as measured by the ring current index Dst and decreases (increases) in the plasmasphere content. The recovery of the plasmasphere after six geomagnetic storm periods is examined; the deduced filling rate is found comparable to the total flux tube filling rates reported by Park (1973) from whistler studies. The rate of the equatorial plasmasphere filling and the rate of decay of the ring current intensity appear to be related, at least for the six events examined. Finally, an empirical relationship between the total plasmasphere content and the equatorial plasmapause position at 1200 LT is derived.