Presentation #110.08 in the session General Topics II — Solar.
Solar flares are extremely energetic rapid events that have the potential to fundamentally alter the structure of the local solar atmosphere in dramatic, and largely unpredictable ways. The locations and characteristics of flare energy deposition can provide insight into the dynamic processes from which these events originate. In this work, we analyzed high-cadence observations of two solar flares with the Interferometric BIdimensional Spectropolarimeter (IBIS), formerly located at the Dunn Solar Telescope (DST) in Sunspot, New Mexico. For each studied flare, the IBIS instrument performed spectral scans of the H⍺ line, including the far blue wing (H⍺-1.3Å). Under the assumption of a “thick-target” chromosphere, emission in the far blue wing of H⍺ is thought to originate in the deep chromosphere as footpoints of overlying loop structures, with emission in these kernel structures produced from the injection of nonthermal electrons during a solar flare. For the first time, we combine modern observations of flare kernel fluctuations with high-quality HXR lightcurve and imaging measurements from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) in order to directly study the relationship between the evolving population of flare-driven nonthermal electrons and rapid fluctuations in blue-wing H⍺ as sites of small scale energy deposition in the low solar atmosphere. We further investigate the structure of the flare region using ultraviolet spectra observed with the Interface Region Imaging Spectrograph (IRIS), in order to constrain the plasma motions in the chromosphere and solar transition region adjacent to the energy deposition layer. Extreme ultraviolet (EUV) images from the Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO/AIA) are also used to determine the structure of the overlying arcade of coronal loops, and track the origins of these bright kernels in relation to low-lying loop structures. This combination of high-quality observations allows us to advance towards a state-of-the-art holistic understanding of flare energetics and deposition in preparation for future studies incorporating the next-generation set of observations that the Inouye Solar Telescope will facilitate.