Understanding the Hot Solar Corona via X-ray Observations with NuSTAR

Abstract: NuSTAR is a highly sensitive direct-focusing hard x-ray (HXR) observatory optimized to observe astrophysical sources. In certain conditions, NuSTAR can also observe the Sun – and characterize faint x-ray emission from sources rarely (or poorly) observed by existing solar-dedicated HXR instruments. In this talk, we will discuss the process of achieving valuable scientific insights about the Sun with NuSTAR, despite observational limitations. We will describe a range of solar results from NuSTAR, particularly highlighting recent efforts using observation of extremely hot (> MK) plasma to investigate the mechanisms that keep the solar corona much hotter than the photosphere. This is the “coronal heating problem”, a major outstanding question in solar physics.