Investigating bidirectional flows in a Quiescent prominence using MAST Ca II 8542 Å line scan observations

Abstract

Quiescent prominences are large magnetic structures hosting cool plasma in surrounding million-degree solar coronae. Prominences host different flows that may distort magnetic field lines, which may lead to magnetic reconnection inside the prominence body. In this study, we investigate bidirectional flow patches in a quiescent prominence. The investigation included the analysis of velocities in the line of sight (LOS) and the plane of sky (POS) of the prominence, complemented with intensity at different spectral positions of the Ca II 8542 & Aring; line. The LOS velocities were obtained using Gaussian fitting to the observed Ca II spectra, whereas the POS velocities were derived from a position-time diagram along a vertical slit in the region of interest (ROI). Complementary to Ca II 8542 & Aring; line scans, EUV intensity images from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory were analyzed to investigate the multithermal nature of the observed bidirectional flows. Out of two ROIs, in the first ROI, a large central patch of bidirectional flow was present initially that merged with other patches and disappeared approximately 30 minutes from the beginning, followed by the generation of another set of patches. Cospatial with diverging LOS motions of order 10 km s-1 associated with patch dynamics, POS motions of similar order were also observed in the ROI. Diverging intensity enhancements in different AIA channels, indicating a multithermal nature of bidirectional flows, were observed cospatially with diverging flows in the POS. Similar dynamics were observed in the second ROI. Bidirectional flow patches and the associated dynamics in LOS and POS may be related to magnetic reconnection inside the prominence.