Japan Geoscience Union Meeting 2025

Presentation information

[E] Oral

P (Space and Planetary Sciences ) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM11] Frontiers in solar physics

Mon. May 26, 2025 10:45 AM - 12:15 PM 302 (International Conference Hall, Makuhari Messe)

convener:Shin Toriumi(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), Alphonse Sterling(NASA/MSFC), Kyoko Watanabe(National Defense Academy of Japan), Shinsuke Imada(Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo), Chairperson:Alphonse Sterling(NASA/MSFC), Kyoko Watanabe(National Defense Academy of Japan)

11:08 AM - 11:30 AM

[PEM11-07] Study of MHD modes population in the mid-corona comparing the radio sounding with MHD simulation and prospects for collaborating with other observations

★Invited Papers

*Shota Chiba1,2, Munehito Shoda3, Takeshi Imamura2 (1.Institute for Space-Earth Environmental Research, Nagoya University, 2.Graduate School of Frontier Sciences, The University of Tokyo, 3.Department of Earth and Planetary Science, School of Science, The University of Tokyo)

Recently, the observation network composed of NASA’s Parker Solar Probe (PSP), ESA’s Solar Orbiter, and BepiColombo has been developed, and solar-observing satellites, such as JAXA’s Hinode and NASA’s SDO, have monitored the sun. According to these missions, observational data around the coronal base and the outer corona are accumulating. Particularly, in-situ observations and numerical models indicated various types of MHD waves contributing to the solar wind acceleration. Among them is an MHD wave decomposition at distances closer than 50 RS using data taken by the first perihelion pass of PSP. However, the data in the mid-corona are still insufficient.
To observationally confirm the underlying physical processes responsible for the formation of the solar wind at distances closer than 10 RS, Chiba et al. (2025; in press) inferred the mode population of density fluctuations observed by radio occultation, which has all been attributed to slow magnetoacoustic waves. Radio occultation observations have been conducted in numerous planetary missions to explore the solar corona. They provide crucial information on the low to mid-corona, which is poorly explored by in situ and even by remote sensing techniques. In Chiba et al. (2025), we compared the radio occultation observations conducted in 2016 using the JAXA’s Venus orbiter Akatsuki with the MHD simulation conducted by Shoda et al. (2021). The time-frequency analysis was applied to the density fluctuations observed by the radio occultation and those reproduced in the MHD model.
This presentation introduces the results obtained from the integrated analysis using the radio occultation and MHD simulation data. Furthermore, we show the prospects for collaborating with other observations from the coronal base to the interplanetary.