Universe of Spectroscopy

Author: Yukio Katsukawa

What would you want to introduce to readers in this series

The Sun is only the star whose active phenomena can be observed in detail. The visible solar surface is less structured, and we can see only sunspots by eye. Spectroscopic observations allow us to see various aspects of the solar atmosphere and its dynamic behavior. Lots of dynamic phenomena are observed especially around a sunspot, and plasma ejections and flares frequently take place there. Our primary research target is to understand mechanisms driving such dynamic phenomena, and to know how they impact our environment around the earth. For doing it, it is essential to obtain physical quantities such as temperatures and velocities in the solar atmosphere. In particular, magnetic field is the most important quantity because its energy is the major source of the activities. Though the Sun is located close to the earth compared with other stars, it is still impossible to measure magnetic fields directly with a magnetometer on site. Our diagnostic tool is to obtain spectra of lights coming from the Sun, which contain lots of information about velocities and magnetic fields. The article presents introduction of various aspects of the solar spectroscopy.

My research field and current interests

My research topic is to understand the heating mechanism of the solar atmosphere using the solar observation satellite “Hinode”. It is anticipated that high-speed flows are detected along with sudden release of magnetic energies using the spectroscopic diagnostics.


Yukio Katsukawa
Solar and Plasma Astrophysics Division
Job Title
Assistant Professor
Field of Expertise
Solar Physics