The x-ray/EUV telescope for the Solar-C mission: science and development activities

Abstract

We report science and development activities of the X-ray/EUV telescope for the Japanese Solar-C mission whose projected launch around 2019. The telescope consists of a package of (a) a normal-incidence (NI) EUV telescope and (b) a grazing-incidence (GI) soft X-ray telescope. The NI telescope chiefly provides images of low corona (whose temperature 1 MK or even lower) with ultra-high angular resolution (0.2-0.3/pixel) in 3 wavelength bands (304, 171, and 94 angstroms). On the other hand, the GI telescope provides images of the corona with a wide temperature coverage (1 MK to beyond 10 MK) with the highest-ever angular resolution (~0.5/pixel) as a soft X-ray coronal imager. The set of NI and GI telescopes should provide crucial information for establishing magnetic and gas-dynamic connection between the corona and the lower atmosphere of the Sun which is essential for understanding heating of, and plasma activities in, the corona. Moreover, we attempt to implement photon-counting capability for the GI telescope with which imaging-spectroscopy of the X-ray corona will be performed for the first time, in the energy range from ~0.5 keV up to 10 keV. The imaging-spectroscopic observations will provide totally-new information on mechanism(s) for the generation of hot coronal plasmas (heated beyond a few MK), those for magnetic reconnection, and even generation of supra-thermal electrons associated with flares. An overview of instrument outline and science for the X-ray photoncounting telescope are presented, together with ongoing development activities in Japan towards soft X-ray photoncounting observations, focusing on high-speed X-ray CMOS detector and sub-arcsecond-resolution GI mirror.