Work

DKIST unveils MHD-predicted sub-50 km photospheric vortices

Year: 2026

Type: preprint

Abstract: Solar vortices are rotating plasma structures that play a key role in the transport of energy and magnetic helicity from the photosphere to the chromosphere and corona. While numerical simulations predict the existence of small-scale photospheric vortices with diameters of 50–100 km, no direct observational evidence has been reported to date, primarily due to the limited spatial resolution of previous instrumentation.Here, we analyze high-resolution observations taken by the 4-meter Daniel K. Inouye Solar Telescope (DKIST) at 416 nm with a spatial resolution of 12.3 km. Using Fourier local correlation tracking and the swirling strength criterion (λci), we identify 201 vortex detections over a sequence of 143 reconstructed frames (approximately 3.2 min) in a field of view of 4.92 × 4.13 Mm, covering a photospheric plage region with pore-like magnetic concentrations.The detected vortices have a median equivalent diameter of 38.6 km (mean 39.5 ± 3.3 km), with virtually all detections below 50 km, placing them in the subgranular regime predicted by magnetohydrodynamic simulations but never previously observed. The median swirling period, τci = 37.3 s, satisfies the τci < 100 s criterion established by MURaM simulations. No statistically significant preference is found for prograde (53.7%) over retrograde (46.3%) rotation, consistent with the negligible role of the Coriolis force at subgranular scales.These results demonstrate the unique capability of DKIST to resolve the photospheric convective vortex population predicted by state-of-the-art magnetoconvection simulations, opening a new observational window into small-scale solar convective dynamics.

Source: Research Square

DOI: 10.21203/rs.3.rs-10990993/v1