Description
Solar flare ribbons have long been used as a diagnostic of the flare reconnection process, where the surface magnetic flux swept out by the ribbons is used to infer the amount and rate that magnetic flux that is reconnected in the solar corona. However, in recent years fine structures such as “kernels”, “spirals” and “blobs” within flare ribbons have been increasingly observed and recognised as a further potential diagnostic for the coronal reconnection process, although their origins are still under debate. Here we present results from a new adaptive-mesh 3D MHD simulation of an eruptive two-ribbon flare. The simulation is highly resolved, such that the flare reconnection enters the bursty, plasmoid mediated reconnection regime. This work builds on our previous analytical modelling of bursty flare reconnection in such flares, where we demonstrated that plasmoids formed in the flare current sheet should map to spirals in the flare ribbons. The simulation demonstrates that in a full dynamic evolution spirals readily form in the flare ribbons and we confirm that they do indeed map to plasmoids in the flare current layer. We further show the how the spirals evolve as the plasmoids form and are ejected, and present some initial efforts to forward model this evolution.
