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

Abstract

Electron density N e distributions in the northern polar region are determined from 1.4 to 5.0 R E 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 N e 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 N e with radial distance. The N e 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.