Solar-C Engineering Study

The Solar-C_EUVST mission will quantify how mass and energy are transferred throughout the solar atmosphere, as a fundamental step towards understanding how energy is transported in magnetised plasmas throughout the Universe, and how the Sun influences the Earth and other planets in the solar system. The complex coupling of plasma and magnetic field in the solar atmosphere is the primary driver of the existence of the heliosphere and the interaction of the solar wind with the planets, yet that coupling is not well understood. Solar-C_EUVST, a single instrument mission, will be the first instrument capable of studying how plasma and energy evolve through the solar atmosphere with matching high spatial and temporal resolution. This directly addresses STFC's roadmap question 'How does the Sun influence the environment of the Earth and the rest of the Solar System?'.

As the top ranked mission concept in an international selection process (Next Generation Solar Physics Mission, NGSPM), and one that builds on the overwhelming success of UK led science and engineering in delivering Hinode-EIS, UK participation in Solar-C_EUVST represents an investment with exceptionally low risk and high reward.

In summer 2018, Solar-C_EUVST was submitted to the STFC priority call, and is on the STFC portfolio of future funding opportunities.

The UK consortium is proposing to provide the following aspects of the instrument under the leadership of MSSL:
1. EUV CCD Assembly (provided by MSSL)
2. CCD Electronics box (provided by MSSL)
3. Telescope deflector (provided by RAL Space)

Solar-C EUVST will provide strong opportunities for future growth in the UK space sector, in particular in the area of high-performance imaging systems. The UK is well established as an expert provider of detector systems, e.g., through Hinode-EIS, and more recently Plato, Euclid and DKIST. TE2V were the industrial provider of CCDs for Hinode-EIS and were subsequently awarded a £10 million contract with the European Space Agency to supply the detectors for Euclid. We will build on this heritage through TE2V becoming the industrial provider of the detectors for Solar-C_EUVST.

In 2016, the Next Generation Solar Physics Mission (NGSPM)'s Science Objectives Team (SOT) was established by NASA, JAXA, and ESA to identify the key outstanding questions to be answered in solar physics. Three top-level science objectives were identified: I) the formation mechanisms of the hot and dynamic outer solar atmosphere, II) the mechanisms of large-scale solar eruptions and foundations for their prediction, and III) the mechanisms that drive the solar cycle and irradiance variation. The Solar-C_EUVST mission, which will address objectives I and II, was selected as the top priority mission concept in this international report. These objectives map directly to the top priority themes S1, S2 and U1 in STFC's Solar System Roadmap. Solar-C_EUVST data will provide clear boundary conditions for space weather models. This is an area of significant UK scientific and governmental interest, with space weather included on the national risk register.

The high resolution and wide temperature range spectroscopy provided by Solar-C_EUVST will enable a full understanding of how energy evolves through the solar atmosphere, that cannot be achieved by any other current or planned facility. The data also provides a benchmark for understanding energy storage and evolution on other stars and astrophysical environments, contributing to STFC priority themes P2 and U2.
Solar-C_EUVST is a natural next step in the carefully cultivated UK scientific collaboration with Japan in solar physics. The Hinode mission is a huge scientific success, having produced ~1500 refereed papers and more than 100 PhD theses produced. The UK has built a deep and trusted relationship with our Japanese colleagues over many years, based on successful cooperation to build and scientifically exploit the Yohkoh and Hinode missions, and this project will ensure that this relationship continues to grow and develop, particularly with at least 17 different UK institutes involved in Solar-C_EUVST science including UCL, RAL Space, Glasgow, St. Andrews, QUB, Warwick, Armagh Observatory, Cambridge, Sheffield, Northumbria and Hull. Japan, US, UK, Italy, Germany, Belgium, and France have all been involved in the development of the instrument design, which builds on the exceptional performance and science return of Hinode/EIS, which is led by the UK.

The industrial partnership will be with Te2V or Andor, again building on relationships that have been fostered over many years and provide benefits to both sides. Te2V is a long-term industrial partner. UK expertise in CCD cameras and our ability to win roles in numerous space missions (Hinode, XMM, Integral, SWIFT, GAIA, Euclid, Plato, SMILE) has been a factor in establishing the pre-eminent position of Te2V CCDs internationally in imaging instrumentation for space science. The recent DKIST UK Consortium partnership with Andor has further demonstrated the benefits to both sectors in terms of generating further commercial applications of sensors developed for solar physics.

The exploitation of data from Solar-C_EUVST will provide significant training opportunities for young scientists within the UK, and enormous opportunities for public engagement at all levels. The UK solar physics community have a long-standing public awareness programme including dozens of talks given to schools each year and frequent media appearances.