Presentation Information
[PEM20-05]Development of a Next-Generation Solar Wind Observation System for Advancing Solar–Terrestrial Coupling Science
*Kazumasa Iwai1, Ken'ichi Fujiki1, Daichi TAKEHARA1, Hirofumi Isogai1, Hao Sato1, Akihiko Ueda1, Tanaka Junnosuke1, Hiroya Miura1, Matsui Ken1, Rikuto Nagashima1, Mutsumi Ueno1, Ruka Tanaka1, Shunsuke Niwa1, Yasushi Maruyama1, Takayuki Yamasaki1 (1.Institute for Space–Earth Environmental Research (ISEE), Nagoya University)
Keywords:
solar wind,coronal mass ejections (CMEs),Interplanetary scintillation (IPS)
Interplanetary scintillation (IPS) is a powerful remote-sensing technique that utilizes radio-wave scattering caused by density fluctuations in the solar wind to diagnose solar wind speed and density structures across interplanetary space. At the Institute for Space–Earth Environmental Research (ISEE), Nagoya University, IPS observations have been continuously conducted for more than 50 years using dedicated radio telescopes in Japan. The current 327 MHz IPS system is used to reconstruct global solar wind structures in the inner heliosphere and to detect transient phenomena such as coronal mass ejections (CMEs). The solar wind and CMEs serve as primary carriers of energy and momentum from the Sun to the Earth, and understanding their propagation processes observationally is a fundamental issue in solar–terrestrial coupling science.
To further enhance this observational foundation, we are developing a next-generation solar wind observation system based on a two-dimensional phased-array configuration. The planned array consists of five cylindrical parabolic antennas aligned in the east–west direction, each extending in the north–south direction. Along the focal line of each cylinder, a large number of high-sensitivity dipole antennas are densely deployed to achieve both a large effective collecting area and wide-field observations. The received signals are fully digitized, and FPGA-based digital beamforming enables simultaneous multi-directional observations. A prototype array corresponding to approximately 30% of the full system is currently under construction at the Fuji Observatory, with the aim of progressively improving observational performance. In parallel, techniques to mitigate increasing artificial radio-frequency interference are being developed to ensure a stable long-term observational infrastructure. These improvements will substantially enhance the spatial and temporal resolution in the inner heliosphere, enabling more quantitative investigations of CME–solar wind interaction processes.
IPS data consist of time series of radio intensity fluctuations. Solar wind speed and disturbance levels are derived through cross-correlation analyses between multiple stations as well as power spectral analyses of the time series. The derived physical parameters are used in tomographic reconstructions of the three-dimensional heliospheric structure. The resulting solar wind information is further validated and refined through comparisons with in situ spacecraft observations, deepening our physical understanding of solar wind structures. In addition, we collaborate with global magnetohydrodynamic (MHD) simulations by computing synthetic IPS signals based on simulated heliospheric plasma distributions, allowing direct comparisons between observations and numerical models. This integrated framework combining IPS observations and MHD modeling is forming a new research infrastructure for data-driven solar wind analysis and space weather forecasting.
To advance the understanding of solar–terrestrial coupling, precise characterization of solar wind structures in the inner heliosphere and their linkage with magnetospheric and upper-atmospheric modeling are essential. The next-generation solar wind observation system will provide upstream information on solar wind structures and compression regions prior to their arrival at Earth, serving as boundary conditions for magnetospheric response studies and upper-atmospheric variability analyses. In this presentation, we report the current progress of the instrumental development and initial scientific outcomes, and discuss the significance of this project as a research infrastructure for solar–terrestrial coupling studies.
To further enhance this observational foundation, we are developing a next-generation solar wind observation system based on a two-dimensional phased-array configuration. The planned array consists of five cylindrical parabolic antennas aligned in the east–west direction, each extending in the north–south direction. Along the focal line of each cylinder, a large number of high-sensitivity dipole antennas are densely deployed to achieve both a large effective collecting area and wide-field observations. The received signals are fully digitized, and FPGA-based digital beamforming enables simultaneous multi-directional observations. A prototype array corresponding to approximately 30% of the full system is currently under construction at the Fuji Observatory, with the aim of progressively improving observational performance. In parallel, techniques to mitigate increasing artificial radio-frequency interference are being developed to ensure a stable long-term observational infrastructure. These improvements will substantially enhance the spatial and temporal resolution in the inner heliosphere, enabling more quantitative investigations of CME–solar wind interaction processes.
IPS data consist of time series of radio intensity fluctuations. Solar wind speed and disturbance levels are derived through cross-correlation analyses between multiple stations as well as power spectral analyses of the time series. The derived physical parameters are used in tomographic reconstructions of the three-dimensional heliospheric structure. The resulting solar wind information is further validated and refined through comparisons with in situ spacecraft observations, deepening our physical understanding of solar wind structures. In addition, we collaborate with global magnetohydrodynamic (MHD) simulations by computing synthetic IPS signals based on simulated heliospheric plasma distributions, allowing direct comparisons between observations and numerical models. This integrated framework combining IPS observations and MHD modeling is forming a new research infrastructure for data-driven solar wind analysis and space weather forecasting.
To advance the understanding of solar–terrestrial coupling, precise characterization of solar wind structures in the inner heliosphere and their linkage with magnetospheric and upper-atmospheric modeling are essential. The next-generation solar wind observation system will provide upstream information on solar wind structures and compression regions prior to their arrival at Earth, serving as boundary conditions for magnetospheric response studies and upper-atmospheric variability analyses. In this presentation, we report the current progress of the instrumental development and initial scientific outcomes, and discuss the significance of this project as a research infrastructure for solar–terrestrial coupling studies.