| Presentation Title: | Does the tip of the cusp in candle-flame-shaped flares trace the bottom of the reconnection current sheet? |
| Author(s): | Ivan Oparin, Sabastian Fernandes, Bin Chen, Chengcai Shen, Xiaocan Li, Sijie Yu, Fan Guo |
Abstract:
The bright cusp-shaped regions observed in candle-flame-shaped flares are generally accepted to be signatures of magnetic reconnection and subsequent plasma energization in solar flares (Tsuneta et al. 1992; Tsuneta 1996). Intense heating and compression in the cusp region can maintain the extreme ultraviolet (EUV) and Soft X-ray (SXR) emission in high-temperature channels for hours. However, it is still an open question whether the reconnection current sheet and associated plasma downflows extend below the tip of the observed cusp and directly energize the EUV and SXR sources. We utilize the multiwavelength observations in EUV and SXR data from SDO/AIA high-temperature channels (131, 94) and Hinode/XRT for two solar flares. By making use of a three-dimensional magnetohydrodynamic flare model by Shen et al. 2022, we localize the Y-points where the reconnection current sheet bifurcates and compare to the observed signatures. To confirm the geometry and orientation of the loops we also employ STEREO observations from a different viewing perspective. We find that although the observed cusp tip in EUV and SXR is the general manifestation of a series of Y points of freshly reconnected field lines projected to the plane of the sky, their spatial distribution is evolving during the gradual phase of the flare and can be located below the cusp tip.