First high-resolution observations of chromospheric swirls with the Dunn Solar Telescope

ABSTRACT We present the first observations of chromospheric swirls using the Hydrogen-alpha Rapid Dynamics camera and Rapid Oscillations in the Solar Atmosphere imaging instruments at the Dunn Solar Telescope. These vortices contribute to heating and dynamics across the solar atmosphere. We analyse the morphology and evolution of 34 swirls and their cospatial bright points (BPs) from the photosphere to the mid-chromosphere. To examine swirl–BP interactions and temporal behaviour, we use image segmentation, Fourier and spectral analysis, and local correlation tracking. The observed swirls have an average lifetime of 7.9 $\pm$ 5 min and diameter of 3.6 $\pm$ 1 Mm, with a positive correlation indicating smaller swirls tend to be short-lived. 76 per cent are associated with a compact BP appearing 12 s to 9 min after swirl formation. Swirl motion is also closely linked to their BP(s) global motions. The swirls exhibit a mean angular speed of 0.04 rad s$^{-1}$, radial speed of 17.7 km s$^{-1}$, and period of 180 s. We observe the formation of a spiral-shaped swirl driven by a BP interacting with a large photospheric vortex. The BP is dragged towards the vortex centre, after which the swirl forms. The BP undergoes changes in orientation and elongation that mirror the swirl’s chromospheric development. A time lag of $-42.5$ s between the sudden change in the BP’s orientation and the peak of the swirl’s intensity variation suggests torsional Alfvén waves may contribute to swirl evolution. Our results support a magnetic origin for swirls rooted in motions of photospheric BPs.