EMIC Waves in Mercury’s Magnetosphere: Statistical Analysis Using Polarization Analysis by the MESSENGER Spacecraft

Mercury possesses an intrinsic magnetic field, much like Earth. However, its strength is about 1% of Earth’s. Because of this small scale, Mercury’s magnetosphere is incredibly dynamic, interacting not only with the solar wind but also with the planet’s own surface.

I study what’s going on inside this magnetosphere—especially what kinds of ions (electrically charged particles) are there, where they are, and how many of them exist by analyzing ElectroMagnetic Ion Cyclotron (EMIC) waves which are excited by ions traveling through the magnetosphere. Right now, I’m working with data from NASA’s MESSENGER Spacecraft to try to uncover the types and distributions of ions around the planet.

This research is expected to be applied to other planets. For example, BepiColombo is scheduled to arrive at Mercury in 2026, and JUICE will begin orbiting Jupiter in 2031. By applying this method, we hope to open new ways to explore particles and plasma environments surrounding planets.(Written by KIKUCHI Riku.)