Reconstruction of plasmaspheric density distributions by applying a tomography technique to jason-1 plasmaspheric TEC measurements

We have developed a tomography algorithm and applied it to a plasmaspheric total electron content data set from Jason-1 satellite (∼1,336 km), which has a Global Positioning System receiver onboard. To invert the measured plasmaspheric total electron content into vertical distribution of electron density, we adopted a multiplicative algebraic reconstruction technique with an assumed initial density distribution. The reconstruction of the plasmaspheric density distribution was performed on Indian (70°E – 90°E), Pacific (200°E – 220°E), and Atlantic (320°E – 340°E) longitudinal planes during the periods of high solar activity (F10.7 > 100) and low geomagnetic activity (Ap < 12) from 2002 to 2005. The reconstructed density distribution displays general climatological characteristics of the plasmasphere. For all three longitudinal sectors, the reconstructed density distributions show weak diurnal variations being greater during daytime (09–15 LT) than nighttime (21–03 LT). In Atlantic sector, the reconstructed plasmaspheric density exhibits an annual anomaly (higher density in December than in June), which was not apparent in other longitude sectors. By fitting the reconstructed density profiles, we derived empirical functions of equatorial plasmaspheric density profiles for 4 months (March, June, September, and December) in the three longitude sectors. The parameters associated with these functions were found to exhibit diurnal variation and annual anomaly characteristics.