Numerical Simulations of Atmospheric Escape

The solar wind and solar EUV radiation stripe away planetary atmosphere into space. The atmospheric escape phenomenon is not only a compelling subject to study the physical mechanisms themselves, but is also important for understanding the evolution of planetary atmospheres, the diversity of planetary atmospheres, and the conditions under which habitable planets can be established. We have developed electromagnetic hybrid (particle ions/fluid electrons) and magnetohydrodynamic (MHD) simulation codes that comprehensively describe the interaction between the solar wind and the ionosphere of unmagnetized planets. We have been clarifying the physical mechanisms and pathways by which the ionized atmospheres of planetary origin removed into space. In addition to the theory and simulations, we are also collaborating with satellite missions and ground-based telescope projects in which Tohoku University participates, in order to elucidate the ionization/neutral atmospheric escape and evolution of the atmosphere of Mars, Venus, and exoplanets, and to understand the conditions for the establishment of habitable planets. (Professor Naoki Terada)