Sara TOMITA Assistant Professor (Research fellowship-PD)


Assistant Professor (Research fellowship-PD)

  • Institute for Advanced Academic Research / Graduate School of Science

  • Keywords

    Particle acceleration, Cosmic rays, Shock waves, Collisionless plasma, Turbulence, Laser plasmas

  • Professional Memberships

    The Astronomical Society of Japan, General Incorporated Association Division of Plasma Physics Association of Asia Pacific Physical Societies

Research Theme

Understanding of Cosmic Rays Acceleration and High-Energy Astrophysical Phenomena


Cosmic rays (CRs), which travel randomly through the universe, are high-energy charged particles that deviate from the Maxwell distribution. The maximum energy of the CRs observed on Earth is 1020eV. Since the discovery of the CRs over 100 years ago, we still don’t understand where and how they are accelerated. CRs also play a crucial role in star formation and galaxy evolution. Clarifying when, where, and how many CRs are produced is one of the important issues in astrophysics.

High-energy astrophysical phenomena that emit X-rays, gamma rays, and high-energy neutrinos are potential sources of the CRs. However, the details of these phenomena remain veiled in mystery. It is believed that plasma outflows ejected from the progenitor stars generate shock waves, where the CRs are accelerated and emit high-energy photons and neutrinos. I study the mechanisms of the CR acceleration and the high-energy photon and neutrino emission in the high-energy astrophysical phenomena using large-scale numerical simulations with supercomputers, laser experiments, and astrophysical observations.