Computational Astrophysics Laboratory

Topics / News

January 14, 2011 | RIKEN RESEARCH
Hydrogen gas: Under pressure
December 18, 2009 | RIKEN RESEARCH
Supernovae host a pasta dinner

About Our Research

We promote the studies of extreme energy cosmic-rays,
space debris removal by high intensity lasers,
and formation and evolution of a life planet.

Investigation of Extreme Energy Cosmic-Rays

EUSO is a new type of observatory that uses the earth's atmosphere as a detector. The sensor is a super wide-field telescope that detects extreme energy cosmic-rays with energy above 1019 eV. EUSO instrument can reconstruct the incoming direction of the extreme energy particles with accuracy better than several degrees. It's observational aperture of the ground area is a circle with 250 km radius and its atmospheric volume above it with a 60-degree field-of-view is about 1 tera-ton or more. The extreme energy particles can be traced back to their origin by their measured arrival direction with accuracy better than a few degrees. EUSO will also observe atmospheric luminous phenomena such as lightning, nightglow, and meteors. We have joined KLYPVE mission to provide a corrector lens, Russian photomultipliers, a laser head to enhance it’s ability sevenfold. Furthermore, space debris observation with EUSO telescope and their remediation by high power pulsed lasers.

JEM-EUSO website

JEM-EUSO image
Artist's conception of the JEM-EUSO telescope observing air shower.

Study of Space Debris removal by high intensity lasers

Space debris are increasing in number in the process of space development. There threat to the spacecraft become significant. In particular, the small objects less than 10cm are believed to be most dangerous. We found that superwide field telescope, developed in EUSO project, can detect and track space debris with the size of 0.5-10cm. We may deorbit them by shooting a high intensity laser beam. We conduct technology development for the debris removal.

Concept of our technical demonstrator of the laser removal of debris aboard International Space Station image
Concept of our technical demonstrator of the laser removal of debris aboard International Space Station. It consists of the EUSO telescope for acquisition and a CAN laser system for tracking and impulse delivery for cm size debris.

Study of Formation and Evolution of a Life Planet

New project of KAKENHI, "Hadean Bioscience" has started in 2014. The laboratory leads the A05 Life Planet Group. We will clarify how the Earth established "Habitable Trinity" in which the materials and energy circulate in three major components: Landmass, Ocean, and Atmosphere. The necessary conditions are

  1. It has a appropriate orbital radius and a small eccentricity so that the surface temperature is always kept in the range of liquid water.
  2. The level of green house effect is appropriate depending on the distance from the central star.
  3. The amount of water is appropriate so that the depth of the ocean is around several km.

We construct numerical model of an accretion disk around a protostar and found that solid particles accumulate at two site in the disk to form planets rapidly.

Planet formation regime image
Planet formation regime

Annual Reports

1995-2001: Japanease documents.
2002-: Japanese/English bilingual documents.

1995 / 1996 / 1997 / 1998 / 1999 / 2000 / 2001 / 2002 / 2003 / 2004 / 2005 / 2006 / 2007 / 2008 / 2009 / 2010 / 2011 / 2012 / 2013 / 2014 / 2015 /


Selected Publications

  1. Toshikazu Ebisuzaki, Shigenori Maruyama, “Nuclear geyser model of the origin of life: Driving force to promote the synthesis of building blocks of life”, Geoscience Frontiers, 8, (2017) 275-298
  2. EUSO collaboration, (corresponding author: Lech Wiktor Piotrowski ), “EUSO-TA – First results from a ground-based EUSO telescope” Astroparticle Physics, 102 (2018) 98-11
  3. T. Ebisuzaki, Y. Imaeda, “United theory of planet formation (i): Tandem regime”, New Astronomy 54, 7-23(2017). doi: 10.1016/j.newast.2016.11.001
  4. T. Nimura, T. Ebisuzaki, S. Maruyama, “End-cretaceous cooling and mass extinction driven by a dark cloud encounter”, Gondwana Research 37, 301-307 (2016). doi: 10.1016/
  5. Toshikazu Ebisuzaki, Mark N. Quinn, Satoshi Wada, Lech Wiktor Piotrowski, Yoshiyuki Takizawa, Marco Casolino, Mario E. Bertaina, Philippe Gorodetzky, Etienne Parizot, Toshiki Tajima, Rémi Soulard, Gérard Mourou, "Demonstration designs for the remediation of space debris from the International Space Station", Acta Astronautica 112, 102-113 (2015)
  6. Ebisuzaki T, Maruyama S. "United theory of biological evolution: Disaster-forced evolution through Supernova, radioactive ash fall-outs, genome instability, and mass extinctions", Geoscience Frontiers 6, 103-119 (2015)
  7. Fumiyoshi Kajino, Toshikazu Ebisuzaki, Marco Casolino, Yoshiyuki Takizawa, Yoshiya Kawasaki, Naoto Sakaki, Sergei Sharakin, Pavel Klimov, Mikhail I. Panashyuk for the JEM-EUSO Collaboration.: "K-EUSO: An improved optical system for KLYPVE ultra-high energy cosmic ray space telescope" Proc. 34th ICRC (Hague), 634 (2015)
  8. The JEM-EUSO Collaboration. "The JEM-EUSO mission: An introduction"
    Special Issue on the JEM-EUSO Mission, Experimental Astronomy 40, 3-17 (2015), ISSN: 0922-6435
  9. Ebisuzaki, T. and Tajima, T. "Astrophysical ZeV acceleration in the relativistic jet from an accreting supermassive blackhole" Astroparticle Physics, 56, 9-15. (2014)
  10. Shirao T, Ueno K, Abe T and Matsuyama T. "Development of DNA markers for identifying chrysanthemum cultivars generated by ion-beam irradiation", Molecular Breeding 31:729-735, (2013)


2005 / 2006 / 2007 / 2008 / 2009 / 2010 / 2011 / 2012


Principal Investigator
Toshikazu Ebisuzaki Chief Scientist
Core Members
Yoshiyuki Takizawa Senior Research Scientist
Tomoki Matsuyama Senior Research Scientist
Marco Casolino Research Scientist
Akira Mizuta Research Scientist
Lech Piotrowski Special Postdoctoral Researcher
Yoshiaki Kato Contract Researcher
Naoto Sakaki Contract Researcher
Tomohiro Tsukihana Technical Staff I
Iriko Kaneko Technical Staff I
Tomoko Ohata Secretary


Address 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
Information Science Building 4F
TEL +81-(0)48-462-1111
ex: 3886
FAX +81-(0)48-467-4078
E-mail cap-labinfo [at]


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