The Solar-C_EUVST mission

High resolution observations with advanced techniques have been improving our knowledge on fundamental physics working in solar atmosphere behaving dynamically. One example is Hinode observations, which have revealed dynamics of elemental magnetic structures, such as chromospheric spicules and photospheric convection, and fundamental physical mechanisms, such as MHD waves, magnetic reconnection, and magneto-convection, occurring in the magnetic structures. Studies on future research directions carried out in Japan and by international science objective team for next generation solar physics mission had led a conclusion that the highest priority is given to high-resolution and high-throughput spectroscopic observations providing plasma diagnostics seamlessly throughout the solar outer atmosphere. Japanese solar community, with US and European colleagues, proposed the mission concept of EUV High-Throughput Spectroscopic Telescope (called the Solar-C_EUVST mission) to JAXA, which has been selected as a candidate for JAXA competitive M-class missions in 2018. Solar-C_EUVST is currently one of two missions that will be considered in the JAXA selection scheduled in December of this year for the FY2024/2025 launch. NASA is currently reviewing the Partner Mission of Opportunity proposal on NASA contributions to the EUVST, and European agencies are also considering their contributions to the EUVST. The proposed mission is designed to comprehensively understand how mass and energy are transferred throughout the solar atmosphere. This is a fundamental step towards answering how the plasma universe is created and evolves, and how the Sun influences the Earth and other planets in our solar system. The onboard science instrument EUVST is an EUV spectrometer with slit-jaw imaging system that will simultaneously observe the solar atmosphere from the photosphere/chromosphere up to the corona with seamless temperature coverage, high spatial resolution, and high throughput for the first time. It is designed to provide an answer to the most fundamental questions in solar physics: how fundamental processes lead to the formation of the solar atmosphere and the solar wind, and how the solar atmosphere becomes unstable, releasing the energy that drives solar flares and eruptions. This talk will provide the overall description of the mission, science, and the latest status to the audience.