Deshpande, Ketaki ; Magdalenic, Jasmina ; Jebaraj, Immanuel Christopher ; Krupar, Vratislav

Poster presented at European Space Weather Week (ESWW) 2023 on 2023-11-20

Abstract: Mapping coronal plasma characteristics from the Sun to Earth is challenging due to limited in-situ observations closer to the Sun and the need for accurately combining and often intercalibration of ground and space-based data. As the accuracy of coronal wind models relies heavily on plasma parameters, it is absolutely necessary to improve and validate these models for better forecasting of solar eruptive events. Our study addresses these challenges by utilizing novel in-situ observations from the Parker Solar Probe (PSP) and Solar Orbiter (SolO), which provide valuable measurements close to the Sun for validating remote sensing observations and modeling outcomes. We focus on type III radio bursts, signatures of fast electron beams traveling along the open or quasi-open magnetic field lines. We first employ ground based imaging Nancay observations for estimation of radio source positions in two-dimensional space. We combine ground based data with the space-based observations carried out by the STEREO and WIND spacecraft, which provide also goniopolarimetric measurements. A radio triangulation method allows us to estimate radio source positions in three-dimensional space, and through. Using the relation between electron density and plasma frequency we estimate the electron densities of the ambient plasma. The obtained radio source positions at different frequencies, i.e. distances from the Sun enable us to derive density profiles along the propagation path of the radio burst. We employ EUHFORIA (EUropean Heliospheric FORecasting Information Asset), a space weather modeling tool to obtain plasma densities at spacecraft and at the radio source positions. We compare our results from radio and in-situ observations with the modeling outcomes. The primary findings reveal significant differences in densities obtained by the two different methods. The density modeled at the PSP positions is generally underestimated in comparison with the in-situ observations. Employing the larger source surface radii (2.9 and 3.0 Rs) in the coronal model of EUHFORIA decreased the discrepancy between the obtained results.

Keyword(s): Type III radio bursts, Radio Triangulation, Parker Solar Probe, Density
Funding: ROB PhD Grant/ROB PhD Grant/ROB PhD Grant