Modeling Regional Electric Field Using EISCAT3D Observations

Abstract

EISCAT3D, which is in its final stage of construction, will be the next generation incoherent scatter radar (ISR) system to provide the full ion velocity vector across hundreds of kms in vertical and horizontal directions. This presents a tremendous opportunity to study the three-dimensional nature of ionospheric electrodynamics. Here we present a data-driven regional model of the electric field based on the EISCAT3D plasma velocity measurements. The measured F-region ion velocity data are fitted to a regional electric potential produced by a grid of spherical elementary systems. The performance of the model is demonstrated using simulated ionospheric parameters obtained from the GEMINI model. To simulate realistic radar measurement of the ion velocity, error estimates obtained from the e3doubt package are added to the ground-truth GEMINI data. Our model can be used with either multistatic or monostatic measurements of the ion velocity, and it can also integrate ion velocity data from other platforms, such as satellite sensors, into existing ISR measurements. The model captures the ground truth electric field including its complex spatial structure with average percentile differences of about 7%. Most accurate results are achieved with the multistatic data, but the general spatial structure of the electric field can be captured also with monostatic data, if optimal beam patterns and regularization are used. The modeling method is also applied using real monostatic line-of-sight ion velocity data measured by the Poker Flat ISR. The modeled electric field shows reasonably well-behaved variations in latitude and longitude within the radar's field of view.