My research field is solar physics with a focus on the dynamic nature of the Sun. We may think that the Sun is a bright ball floating in the sky and shows us an unchanged figure, though the Sun is actually a very dynamic star. In a short time scale of hours or so, explosive phenomena such as solar flares and coronal mass ejections occur on the Sun, while in a long time scale of years or so, magnetic activity on the Sun changes almost periodically, which is known as 11-year solar cycle. The goal of my research is to clarify the physical mechanism of short-term and long-term solar activity where the magnetic field is supposed to play a fundamental role. Toward this end, I have been conducting observational and theoretical researches to investigate dynamic processes involved in the solar activity, which are listed below:

 • Cyclic amplification of magnetic fields in the solar interior (solar cycle)
• Transport of magnetic fields through the solar convection zone (magnetoconvection)
• Emergence of magnetic fields into the solar atmosphere (flux emergence)
• Formation of magnetic structure in the solar atmosphere (sunspot, active region, flux rope, prominence/filament)
• Heating and explosion of magnetic structure in the solar atmosphere (solar atmospheric heating, sigmoid, solar flare, jet)
• Ejection of magnetic fields toward the interplanetary space (solar wind, coronal mass ejection)

 The solar activity affects the Earth in both time scales. In the short time scale, flares and coronal mass ejections produce high-energy particles and magnetized plasma blobs traveling through the interplanetary space, which potentially impact on terrestrial environment by damaging artificial satellites and ground-based electric facilities. This is the subject of space weather. On the other hand, the long-term variation of the solar activity may influence the climate of the Earth (space climate). This indicates that the physical state of the Earth where we are living depends on the solar activity, and it is therefore important to have a view of the Earth inside the Sun, or the Earth in solar fields (solar gravitational field, solar radiative field, and solar magnetic field).

研究室s