Jets in the Solar Atmosphere

Prototype of explosions in the solar atmosphere
Solar Jets

Jets in the Solar Atmosphere

I have been trying to understand the release of magnetic energy in the solar atmosphere since I was an undergraduate student. Although it is well known that dynamic phenomena in the solar atmosphere are driven mainly by “magnetic reconnection,” it cannot explain everything. To fully explain these phenomena, we need to understand how magnetic energy is converted into thermal energy, plasma kinetic energy, and non-thermal-particle kinetic energy. To achieve my scientific goal, I am investigating jet phenomena in the solar atmosphere based on the observing data with a broad wavelength range, from radio to X-rays.

Solar Cycle

Why do sunspots change periodically?

Image Credit: NAOJ/ISAS
Solar Cycle

Observational Studies of Solar Cycle

The number of sunspots changes periodically, and its period is about 11 years. The fact is well known since the 18th century, but we cannot answer the question "Why sunspots change periodically?" yet. To solve the problem and understand the periodical variation of the solar atmosphere, I'm studying solar-cycle issues observationally, especially using solar radio data.

Solar Observations with ALMA

Development of solar observing method with ALMA
olar observations with ALMA

Solar Observations with ALMA

The Atacama Large Millimeter/submillimeter Array (ALMA) is the largest radio interferometer in the world for observing the celestial objects, mainly star formation region, high-z galaxy, molecular cloud. ALMA has a capacity of observing the Sun too, but the development of solar observations had not been done until 2010. We developed the solar observing method with Band3 (100 GHz) and Band6 (239 GHz) and started to offer solar observations to scientists in 2016. The development is continued for adding new functions of observing the Sun.

Nobeyama Radio Polarimeters

The radio telescopes for measuring solar fluxes with multiple frequencies in microwave range

Image Credit: NAOJ
Nobeyama Radio Polarimeters

Nobeyama Radio Polarimeters (NoRP)

Nobeyama Radio Polarimeters (NoRP) are observing the Sun with multiple frequencies in the microwave range. It is capable to obtain the total coming flux and the circular-polarization degree. The system of 17 GHz is routinely working since 1978, that of 35 GHz since 1983, and that of 80 GHz since 1984. The systems of 1, 2, 3.75, and 9.4 GHz were working at Toyokawa observatory of the Research Institute of Atmospherics, Nagoya University since around 1979. They were moved to Nobeyama in Apr 1994 and has been working since then. I am contributing to the operation of NoRP as a manager since 2019.

"Hinode" Satellite (SOLAR-B)

The microscope for the Sun

Image Credit: NAOJ

"Hinode" Satellite (SOLAR-B)

The solar observing satellite “Hinode” was launched from Uchinoura Space Center on September 23, 2006 (JST). “Hinode” has three telescopes to observe the Sun. The cylindrical main body of the satellite is the Solar Optical Telescope (SOT) which observes in visible light. The cylinder attached beneath the main body is the X-Ray Telescope (XRT). The Extreme-ultraviolet Imaging Spectrometer (EIS) is mounted to the upper surface of the main body. These innovative telescopes can capture the movement of the complex solar magnetic fields and the three-dimensional motions of the plasma in real time.
I joined the Hinode project since 1999 and contributed the development of the X-Ray Telescope (XRT), Attitude Control System, Mission Operation and Data Analysis (MODA) and the establishing of Hinode Science Center at NAOJ. After launching "Hinode", I have been contributing to Public Outreach (2006 - 2013) and XRT Scientific Operation (2006 - present).

"YOHKOH" Satellite (SOLAR-A)

Observed solar flares and established its magnetic reconnection model

Image Credit: JAXA

"YOHKOH" Satellite (SOLAR-A)

"Yohkoh" is the 2nd solar observing satellite of Japan and was launched on 30 August 1991 (JST). The satellite's objectives were observations of solar flares during a maximum period of solar activity and revealed the physical mechanism of solar flares.
When I was an undergraduate student, I joined the Yohkoh project and started my career as a solar physics researcher. I investigated mainly solar X-ray jets discovered with Yohkoh satellite (Shibata et al. 1992 and Strong et al. 1992) and got a doctorate in March 1999.

  • Final images observed with Soft X-ray Telescope aboard Yohkoh satellite (2001/12/15).
  • My Doctoral Thesis
  • Link: Yohkoh Homepage (written in Japanese)

Solar Data-Analysis Systems

Developments of computer systems for analyzing solar data
Solar data-analysis systems

Solar Data-Analysis Systems

For analyzing the solar data obtained with the solar telescopes on the ground and orbit, the computer system that is optimized for solar data-analysis is essential. I have contributed to the development and operation of the computer system for analyzing the data obtained with Hinode satellite, solar radio telescopes at Nobeyama and Yohkoh satellite, since when I was a graduate student.


My articles carried on scientific journals


Teaching Experience

Lectures for graduate/under-graduate students
Supervised students
Teaching Experience

Teaching Experience

  • Lectures for graduate/under-graduate students
    • Lecture “Astronomy I and II”
      at Faculty of Letters, Keio University (Apr. 2019 - Present)
    • Face-2-Face Course "Basic of Observational Astronomy"
      at Gunma Study Center, The Open University of Japan
      (Oct. 2019, Nov 2020)
    • Spring School “Solar Physics”
      at SOKENDAI/NAOJ (Feb. 2018)
    • Intensive Course “Basic of Solar Physics”
      at Ibaraki University (Jul. 2013)
    • Intensive Course “Solar Eclipse”
      at Tokai University (Jun. 2008)
    • Intensive Course “Physics of Solar Atmosphere”
      at Ibaraki University (May 2008)
    • Intensive Course “Basic of Solar Physics”
      at Shiga University (Dec. 2002)
  • Supervised Students

Public Outreach

Lectures and publications for genenal public
Public Outreach

Public Outreach


ALMA project,
National Astronomical Observatory of Japan,
National Institute of Natural Science

Concurrent appointment in NAOJ

- Solar Science Observatory
- Astronomy Data Center

Academic & Professional Experience

  • Dec. 2019 - Present: Associate Professor
    ALMA Project, NAOJ/NINS
  • Apr. 2019 - Present: Part-time Lecturer
    Faculty of Letters, Keio University
  • Apr. 2015 - Nov. 2019: Assistant Professor
    ALMA Project, NAOJ/NINS
  • Apr. 2005 - Mar. 2015: Assistant Professor
    Nobeyama Solar Radio Observatory, NAOJ/NINS
  • Apr. 2004 - Mar. 2005: Research Fellow
    Nobeyama Solar Radio Observatory, NAOJ/NINS
  • Apr. 2000 - Mar. 2004: Assistant
    Nobeyama Solar Radio Observatory, NAOJ/NINS
  • Apr. 1999 - Mar. 2000: Postdoctoral Fellow
    YOHKOH Satellite Project, ISAS/JAXA



Professional Affiliations

International Astronomical Union / Astronomical Society of Japan / American Geophysical Union / Japan Geoscience Union / Japan Solar Physics Community / Japan Radio Astronomy Forum

Journal Referee

Science / Astrophysical Journal / Astronomy & Astrophysics / Monthly Notices of the Royal Astronomical Society / Solar Physics / Publication of the Astronmical Society of Japan/ Journal of Atmospheric and Solar-Terrestrial Physics

Committee services

  • Oct. 2018 - Present
    Commission E3, Division E, International Astronomical Union
  • Dec. 2017 - Present
    Steering Committee of Japan Solar Physics Community
  • Apr.2012 - Jun. 2018
    Advisory Committee for Solar and Plasma Astrophysics, NAOJ
  • Apr. 2012 - Mar. 2016
    Advisory Committee for Astronomy Data, NAOJ
  • Apr. 2011 - Mar. 2015
    Consortium for Science Operation of Nobeyama Radioheliograph, NAOJ
  • Oct. 2002 - Sep. 2004
    Executive Committee of General Meetings, Astronomical Society of Japan

Masumi Shimojo