What Will NuSTAR Observe from the Sun?

The Nuclear Spectroscopic Telescope Array (NuSTAR) is the first hard X-ray focusing optics satellite, observing from 2-79 keV. While designed and built as an astrophysics mission, the NuSTAR science and operations team has committed to three weeks of solar observing time in 2014. The high effective area and low background of NuSTAR give it a sensitivity 200x that of RHESSI at 10 keV, with even greater sensitivity at lower energies. NuSTAR solar pointings are therefore an excellent opportunity to search for HXR emission from coronal nanoflares and other low-luminosity HXR sources. These include the possible hot (>5 MK) plasma component of non-flaring (at GOES sensitivity levels) active regions, as well as weak coronal bremsstrahlung from the electron beams responsible for type-III radio bursts. In order to more effectively analyze the NuSTAR solar data, we simulate several cases (quiet-Sun, active regions, solar flares) using the end-to-end observatory simulation environment NuSIM. NuSIM includes the effects of stay light, single-bounce "ghost rays", and the effects of instrument deadtime on the throughput. We have modified the software to simulate Sun-pointed observations, including the loss of several instruments used for standard aspect reconstruction during astrophysical observations and the spectral distortions caused by pile-up in the detectors during the extreme count rates expected during the solar observations. We concentrate our simulations on nanoflares across a wide (thermal and non-thermal) parameter space.