| Authors : | Sripan Mondal (Department of Physics, Indian Institute of Technology (BHU), Varanasi-221005, India); A.K. Srivastava (Department of Physics, Indian Institute of Technology (BHU), Varanasi-221005, India); Sudheer K. Mishra (Indian Institute of Astrophysics, Kormangala, Bangalore, India); K. Sangal (Department of Physics, Indian Institute of Technology (BHU), Varanasi-221005, India); Pradeep Kayshap (Vellore Institute of Technology (VIT) Bhopal, 466114, India); Yang Guo (School of Astronomy and Space Science, Nanjing University, China); David Pontin (School of Information and Physical Sciences, University of Newcastle, Australia); Vadim M. Uritsky (Catholic University of America and NASA-GSFC, USA); Leon Ofman (Catholic University of America and NASA-GSFC, USA; Visiting, Tel Aviv University, Israel); T.-J. Wang (Catholic University of America and NASA-GSFC, USA); Ding Yuan (Institute of Space Science and Applied Technology, Harbin Institute of Technology, Shenzhen 518055, China)
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| Abstract : | We analyze multiwavelength observations of the propagating intensity disturbances (PDs), discovered by Atmospheric Imaging Assembly (AIA) onboard Solar Dynamics Observatory (SDO) to extract out information about its driving mechanism and physical nature. We observe two elongated curved magnetic flux tubes in the localized corona to approach and merge with each other followed by the generation of brightening, which further propagates in a cusp-shaped magnetic channel. We probe an occurrence of heating in this region-of-interest (ROI) via Differential emission measure analysis . We extrapolate potential magnetic field lines at coronal heights from observed Helioseismic and Magnetic Imager (HMI) vector magnetogram via Green’s function method using MPI-AMRVAC. Furthermore, we inspect the field to locate magnetic nulls and quasi-separatrix layers (QSLs) which are preferential locations for magnetic reconnection. We find the existence of dominant QSLs including a magnetic null which is matching the geometry followed by PDs, therefore, it provides conclusive evidence of magnetic reconnection. PDs are observed to exhibit periodicities of around four minutes. The speeds of PDs measured by Surfing transform technique are similar to each other in three different SDO/AIA bandpasses, i.e., 171, 193 and 131 Å which therefore cancel out the interpretation of PDs in terms of slow magnetoacoustic waves. We describe comprehensively the observed PDs as quasi-periodic plasma flows generated due to periodic reconnection in the vicinity of a coronal magnetic null.
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