Volumetric Ion Composition Fitting Technique for EISCAT3D

by Ayanew Nigusie (University of Oulu)

EISCAT3D will be an invaluable instrument to study the volumetric structures of
the ionosphere. Yet, optimal data-analysis tools need to be developed to fully
exploit this unprecedented capability. ISfit is a data analysis tool that
enables optimal plasma parameter fitting using data from multiple multibeam
receivers of an EISCAT3D-like radar system. O⁺ ion fraction fits to
field-aligned incoherent scatter radar measurements are enabled by the Bayesian
Filtering Module (BAFIM), which applies Bayesian filtering in time and
smoothness priors in range, coupled with the Ion Density Calculator (IDC)
chemistry model. By combining the BAFIM–IDC technique with ISfit and binning
the data in magnetic latitude and longitude, one can make volumetric fits of
the O⁺ ion fraction and several other plasma parameters. We apply this
technique to estimate 2D plasma parameters, including ion composition, using
measurements from meridional scans of the EISCAT Svalbard Radar (ESR) 32-m
antenna. "