Recommendations from the NGSPM-SOT report and mission opportunities in Japan

A study report on the future of solar physics for the decade of 2020 was published by the Next Generation Solar Physics Mission (NGSPM)’s Science Objectives Team (SOT), an advisory team consisting of 14 scientists, chartered by NASA, JAXA, and ESA. The report lists scientific objectives in all the research areas related to solar physics and provides priorities for next generation solar physics missions to be realized in the mid 2020s. The report is based on extensive reviews of the broad interests of the heliophysics research community, following a public call for white papers in the fall of 2016 which resulted in 34 submissions covering a wide variety of topics. Three top-level science objectives are identified: I) Formation mechanisms of the hot and dynamic outer solar atmosphere, II) Mechanisms of large-scale solar eruptions and foundations for predictions, and III) Mechanisms driving the solar cycle and irradiance variation. There are two broad avenues, both with distinct merits, for future research: physical mechanisms on elemental scales, versus global processes affecting/involving large fractions of the solar interior and/or atmosphere. With the resources available for a NGSPM in the next decade, the team chose to focus its recommendations on the study of fundamental physical processes at high spatial and temporal resolution through all temperature regimes of the solar atmosphere. For this study, the SOT identified a minimum set of , i.e., three kinds of instruments with which NGSPM can address the greatest number of sub-objectives and maximize the science return of the mission. The team recommends that these instruments be realized with a single platform. If the single-platform approach is not possible, a combination of two or three spacecraft is recommended. In response to the NGSPM report, the Japanese solar physics community has been making efforts to realize a part of such instruments in the mid 2020s and submitted the Solar-C_EUVST mission proposal to ISAS/JAXA in reply to 2017 Announcement of Opportunity for competitive M-class mission launched by an Epsilon rocket. This mission carries an EUV high-throughput spectroscopic telescope (EUVST) and aims to mainly cover topics I) and II). This talk will briefly discuss recommendations in the NGSPM-SOT report and Japanese efforts to the recommendations.