Description
Solar flares are caused by magnetic reconnection in active regions (ARs). Sometimes, similar flares can recur in the same AR, known as homologous flares. This study investigates whether magnetic reconnection follows the same process in two homologous flares of AR12146.
We examined the morphologically similar flare ribbons and diagnosed their magnetic topology using quasi-separatrix layers (QSLs) from nonlinear force-free field (NLFFF) extrapolation. Key findings include:
1) Differences between ribbon epicenter locations of the two flares, where pre-flare brightenings are found, suggesting micro-reconnections trigger the flares.
2) While QSL traces remain consistent, flare ribbons show different behaviors relative to the QSLs, with one flare exhibiting a ribbon extending beyond a QSL, indicating a distinct flux system being reconnected. EUV flare loops further suggest different post-flare connectivity is built by the two flares.
We propose that micro-reconnections at varied sites lead to different reconnection sequences in AR12146. On the other hand, the preservation of large-scale topology results in most reconnected flux systems being shared by the two flares, explaining the homologous nature of these flares. These insights enhance our understanding of micro-reconnection as a possible mechanism driving flare recurrence and the role of magnetic topology in solar flares.
