Electron density distribution over the northern polar region deduced from IMAGE/radio plasma imager sounding

Abstract

Electron density Ne distributions in the northern polar region are determined from 1.4 to 5.0 RE at invariant latitudes greater than 70° using the radio plasma imager (RPI) on the IMAGE satellite over the period from June 2000 to November 2001. An empirical Ne model in this region is derived as a function of radial distance and geomagnetic activity. A power law with a power index of −5.09 ± 0.03 describes the variation of Ne with radial distance. The Ne appears to increase exponentially with the Kp index. The altitude dependence of the empirical model at low geomagnetic activity is qualitatively consistent with previous models derived from the ISIS 1 and the Dynamic Explorer 1 spacecraft.