The Solar eruptioN Integral Field Spectrograph (SNIFS) Sounding Rocket

The lower solar atmosphere is temporally dynamic and spatially inhomogeneous, and it is becoming increasingly clear that this complex activity must be measured and quantified if we are to fully understand how mass and energy are transported into the corona. The Solar eruptioN Integral Field Spectrograph (SNIFS) sounding rocket is designed to break new ground by using a unique set of capabilities to probe the most vexingly complex region of the solar atmosphere, the chromosphere. Hydrogen Lyman-alpha (Ly-α; 121.6 nm) is the brightest line in the solar UV spectrum, it is energetically one of the most important. Using radiation transfer models, we can use the observed line profiles to reconstruct the transit of these photon through the solar atmosphere and understand the plasma from which they came. SNIFS will observe not only Ly-ɑ, but the nearby Si III and O V emissions, two transition regions lines that allow us to observe how the chromosphere connects with upper atmosphere. The SNIFS rocket mission has a primary objective to explore the energetics and dynamics of chromosphere using a next-generation solar spectral imager.

SNIFS will be the first of its kind: a solar ultraviolet integral field spectrograph (IFS; Chamberlin and Gong, 2016). SNIFS technology will revolutionize solar observations by obtaining high cadence 3D information simultaneously: two spatial dimensions and one spectral dimensions.SNIFS utilizes a novel optical design to simultaneously observe a 32 x 32 arcsec field of view with 0.45 arcsec pixels, with a spectral resolution of 66mÅ and at 1 s cadence. The SNIFS design employs, for the first time in a spaceflight instrument as a technology development, a 72x72 element 2D array of reflecting and focusing mirrorlets, allowing IFS concepts to move down into EUV wavelengths. This mirrorlet array is placed at the imaging plane of the telescope, similar to the location of a slit in a traditional imaging slit-spectrometer design. After the mirrorlet in the optical path, a focusing grating will then produce a high-resolution spectrum for each spatial element defined by the mirrorlet elements. SNIFS's IFS technology is truly a game-changing instrument needed for future solar physics missions, and was recently selected and funded by NASA to fly in Spring of 2024.