受賞区分：国内学会・会議・シンポジウム等の賞  受賞国：日本国

受賞区分：国内学会・会議・シンポジウム等の賞  受賞国：日本国

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11207-022-01968-9

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Monthly Notices of the Royal Astronomical Society  

A radio link directly probing the inner solar corona offers the possibility to characterize solar wind properties, including velocity, density, turbulence, and even the axial ratio. In this study, we leveraged radiometric data obtained during a joint superior solar conjunction of the ESA/JAXA BepiColombo mission and the JAXA Akatsuki mission. Our objective is to ascertain the solar wind velocity by analysing Doppler-shift timeseries of radio signals exchanged between the two spacecraft and two distinct ground stations. We conducted a cross-correlation analysis to determine the travel time of large-scale plasma density fluctuations as they intersect with the downlink signals of both spacecraft. This method is applied to the data collected on 2021 March 13 and 2021 March 14. The analysis of the March 13 data has shown that the two Doppler residuals timeseries present a clear correlation at a time-lag of 2910 s. Using the knowledge of the relative distance between the two probe-ground station lines of sight at the closest approach to the Sun, we estimated the solar wind velocity to be 421 ± 21 km s−1. Following the same procedure for the second experiment, we estimated the solar wind speed velocity to be 336 ± 7 km s−1. These results are compatible with the sampling of the slow solar wind at heliographic latitudes of −22◦ and −26◦, respectively.

DOI： 10.1093/mnras/stae1929

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