The STIX imaging concept

Abstract: 

The Spectrometer/Telescope for Imaging X-rays (STIX) is the instrument on board the ESA Solar Orbiter mission dedicated to the observation of solar flares. The telescope provides key diagnostics on the temperature of the heated plasma and on the electrons that are accelerated at non-thermal energies by measuring the corresponding bremsstrahlung emission. Since focusing X-rays is a challenging task, the instrument applies an indirect imaging technique, and measures a limited number of Fourier components of the angular distribution of the X-ray sources. Therefore, the imaging problem for STIX consists in reconstructing the image of the X-ray sources by solving a Fourier inversion problem from limited data.

In this talk, we will provide an overview of the STIX imaging concept and of the computational techniques that have been implemented for reconstructing images from STIX data. We will also describe an imaging-spectroscopy technique that has been recently implemented and allows the reconstruction of images of the flaring electron distribution.