New Types of the Chromospheric Anemone Microflares: Case Study

Abstract

The chromospheric anemone microflares (AMF) are the transient solar phenomena whose emission regions have a multi-ribbon configuration. As distinct from the so-called "atypical" solar flares, also possessing a few ribbons, the temporal and spatial scales of AMFs are a few times less, and the configuration of their ribbons is more specific (star-like). The previously reported AMFs had typically three or, less frequently, four ribbons; and it was shown in our recent paper (Dumin and Somov: 2019, Astron. Astrophys. 623, L4) that they can be reasonably described by the so-called GKSS model of magnetic field, involving as few as four point-like magnetic sources with various polarity and arrangement. To seek for the new types of AMFs, we performed inspection of the large set of the emission patterns in the chromospheric line Ca II H recorded by Hinode/SOT and confronted them with the respective magnetograms obtained by SDO/HMI. As follows from this analysis, it is really possible to identify the new unusual AMFs. Firstly, these are the flares occurring in the regions with unbalanced magnetic flux. Secondly, and most interesting, it is possible to identify the AMFs with much more complex spatial configurations, e.g., involving five luminous ribbons with a nontrivial arrangement. As follows from the corresponding magnetograms, they are produced by the effective magnetic sources (sunspots) of different polarity with intermittent arrangement, but their number is greater than in the standard GKSS model.