The Striated Solar Photosphere Observed at 20-km Resolution

Striations observed at the boundaries of magnetic flux elements in the solar photosphere represent one of the smallest-scale phenomena on the Sun, arising from the complex interaction of strongly coupled hydrodynamic, magnetic, and radiative properties of the plasma. The Daniel K. Inouye Solar Telescope (DKIST) allows observations of the solar atmosphere with a spatial resolution of about 20 km with its current instrumentation. We analyze images acquired with the Visible Broadband Imager using the G-band channel to investigate the characteristics of fine-scale striations in the photosphere and compare them with state-of-the-art radiation-MHD simulations at similar spatial resolution. Both observed and synthetic images reveal photospheric striae with widths of approximately 20−50 km, suggesting that at least 4-m class solar telescopes are necessary to resolve these ultrafine structures. Analysis of the numerical simulations shows that the striation observed in the filtergrams is associated with spatial modulation in the photospheric magnetic field strength, which cause shifts in the geometrical height where the emergent intensity forms. Some fine-scale striations in the synthetic images originate from magnetic field variations of approximately 100G, resulting in Wilson depressions as narrow as 10 km. This suggests that DKIST G-band images can trace the footprints of magnetic field variations and Wilson depressions at a similar scale.