Comparison of electric fields measured at F-region heights with 150 km - irregularity drift measurements

Abstract

The potential to observe the E-W electric field in the equatorial ionosphere using the strong coherent echoes obtained by the Jicamarca radar from irregularities present at the Magnetic Equator, in the altitude range between 135 and 175 km, has been established by Kudeki and Fawcett (September, 1993). They based their claims by comparing vertical drift measurements at these altitudes with simultaneous ground magnetogram records made in Ancon, which showed a high non linear correlation between the two. In this paper we present more direct correspondence by comparing simultaneous measurements made at F-region heights, using the standard I.S. technique with measurements made using the coherent echoes at the 135-175 km altitude. The correspondence is one to one. In addition, it is shown that there is also correspondence between the E-W drifts (vertical component of the electric field) measured at these two altitude ranges. Furthermore, it is shown that samples taken, for the last 3 years, at the 190 km nominal altitude, with the usual Jicamarca F-region drift mode, are strongly "contaminated" by the filtered tail from the stronger lower altitude coherent echoes and carry the same vertical drift information. The correspondence again is one to one, with the added advantage that their error bars are much smaller. This "contaminated" data was excluded in the past from the usual analysis. We are now recovering it to produce cleaner vertical and E-'N drifts drift series during the day. The new data presents special advantages in studding the effects of magnetic storms at a highcr resolution. Previously, one minute resolution data was too noisy to detect small and fast electric field perturbations.