Equatorial zonal electric fields inferred from a 3-D electrostatic potential model and ground-based magnetic field measurements

We present a new technique to infer quiet time zonal electric fields in the daytime equatorial ionosphere. The electric field inference technique utilizes a threedimensional (3-D) electrostatic potential model of the low-latitude ionosphere constrained by ground-based magnetic field measurements. To test this technique, inferred zonal electric fields for the Peruvian sector in Jicamarca (11.95°S, 283.13°E, 0.6°N dip latitude) were compared with zonal electric field (vertical drift) measurements made by the Jicamarca Incoherent Scatter Radar. The comparison shows a good agreement between the inferred and measured electric fields. An example of electric field estimation for Davao (7.4°N, 125.4°E, 0.58°S dip latitude) in the Philippines sector is also presented in this report. Inferred electric fields for Davao are in good agreement with F region vertical plasma drifts measured by drift sensors onboard the AE-E and ROCSAT-I satellites on that longitude sector. Our results suggest that realistic estimates of quiet time zonal electric fields for the equatorial ionosphere can be obtained from the 3-D potential model whenever observatory magnetic field measurements are available.Copyright 2009 by the American Geophysical Union.