MPS Seminar: Slitless Spectroscopy for the Solar Corona - A New paradigm from MaGIXS (Athiray Panchapakesan)

Imaging of the Sun at high energies in EUV and X-rays have revolutionized our understanding of the outermost atmosphere of the Sun, the solar corona. Precise determination of plasma diagnostics including temperature, density, abundances, line-of-sight velocities require spectroscopy. Traditionally, slit-based instruments probe the Sun with high spectral resolution through long, narrow slits. 2D pure spectral images are created by stepping the slit, called raster, over the region of interest. During the raster process, we lose co-temporal observations of the spatial structures. This difficulty can be overcome with slitless spectrograph instruments, which can take a snapshot of a wide field of view on the Sun, with dispersed spectral images overlapped from different spatial locations on the Sun. Such instrument was last flown successfully in Skylab and were abandoned since 1970s due to the difficulty of unfolding the overlapping spatial and spectral information. Such data are called spectroheliogram (or) overlappogram. Recently, novel inversion algorithms have been successfully demonstrated to unlock the potential of slitless spectrographs. The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS), a NASA sounding rocket mission, pioneered measurement of the soft X-ray overlappogram of the solar corona. During its first flight, MaGIXS-1 observed several diagnostic emission lines to constrain frequency of heating in active region loops. Here, I will present an overview of overlappogram instruments, showcase science highlights from MaGIXS-1 flight, and finally describe plans for the upcoming MaGIXS-2 rocket campaign, scheduled for July 2024.