The Daniel K. Inouye Solar Telescope captures ambient shock waves ignited by magnetic vortices

One of the first high-cadence chromospheric image sequences recorded with the recently commissioned Daniel K. Inouye Solar Telescope (DKIST) has revealed propagating arc-shaped bright fronts of a few hundred kilometers width. These bright fronts maintain their arc shape over up to one minute, travel with apparent horizontal speeds of ∼8 km s−1, and originate from chromospheric bright grains seen at the center of the arc. We identify photospheric G-band bright points underneath the chromospheric bright grains, which are typically the signature of small-scale magnetic flux concentrations. The G-band bright points are found to interact with colocated vortices prior to the appearance of the chromospheric bright fronts. Images synthesized from three-dimensional magnetohydrodynamic simulations show a striking similarity with the discovered phenomenon and reveal that the arc-shaped bright fronts arise from essentially acoustic, weak shock fronts that propagate in the ambient medium, seemingly triggered by the vortex dynamics of the underlying magnetic flux concentration. In this work, we provide the first hints of a hitherto unknown magnetohydrodynamic process by which vortex-driven torsional Alfvén pulses couple to predominantly acoustic waves that steepen into shocks and dissipate their energies. The detected number density and frequency of these events are at least a factor 10 too small to be a major source of solar chromospheric heating but simulations show a seven times higher number density. We therefore expect to discover many more events with tailored narrow band observations.