Inter-calibration and statistical validation of topside ionosphere plasma density observations made by CSES-01 mission.

$In situ$ probing of the topside ionosphere plasma through Langmuir Probes (LPs) on-board low Earth orbit (LEO) satellites is of outstanding importance to get information both on the electron density (Ne) on a global scale and in regions difficult to probe with ground-based instrumentations. Moreover, data collected by LEO satellites in the topside ionosphere are the raw material on which ionospheric empirical models like the International Reference Ionosphere (IRI) rely to describe the spatial and temporal variations exhibited by Ne in the topside ionosphere. LP $in situ$ Ne measurements collected by CSES-01 mission offer the opportunity of improving the current knowledge and modeling capabilities of the topside ionospheric plasma. Data recorded in the years 2019-2021 are first compared with corresponding data recorded by instruments on-board the ESA Swarm B satellite and with values modeled by IRI. In a second stage, CSES-01 Ne data are calibrated through corrected Swarm B Ne LP data. Finally, the goodness of the calibration procedure is validated through a statistical comparison with Ne observations from Incoherent Scatter Radars located at Jicamarca, Arecibo, and Millstone Hill.