Abstract Details


Name: Sandeep Kumar Dubey
Affiliation: Udaipur Solar Observatory, Physical Research Laboratory, Udaipur, Rajasthan, India
Conference ID: TVS202510185
Title: Multi-height Study of the Chromospheric Inverse Evershed Flow and its Association with Photospheric Flows
Authors and Co-Authors: Debi P. Choudhary, Shibu K Mathew, Sandeep K Dubey
Abstract Type: Contributory Presentation
Abstract: Sunspots are strongly magnetised regions, with a central dark umbra and relatively bright and filamentary penumbra in the photosphere. In the chromosphere, sunspots are surrounded by a canopy of fibrils known as the superpenumbra, which hosts an inflow of plasma toward the sunspots, known as inverse Evershed flow (IEF). We analysed the IEF across multiple layers of photosphere and chromosphere around a sunspot (NOAA 13131) using line scan observations in the Fe I 6173 Å and Ca II 8542 Å spectral lines, acquired using the Multi-Application Solar Telescope (MAST), Udaipur, complemented with data products from the HMI/SDO. Line-of-sight (LOS) velocities were obtained for different bisector levels in both spectral lines. Additionally, the Ca II 8542 Å spectra were inverted using a Non-LTE Inversion Code (NICOLE) to retrieve the temperature and velocity stratification over different layers of the lower solar atmosphere. We observed that the IEF evolved dynamically in time and with height in the solar atmosphere. The flow speed associated with the IEF channels was on the order of 8 km/s in the upper chromosphere, which decreased in the lower layers of the atmosphere. The flow was traced to the lower chromosphere in LOS velocity maps and the upper photosphere in intensity images. The temperature enhancements associated with the IEF were up to 300 K at log τ ≈ −2 and 800 K at log τ ≈ −6 near the end point of one channel. The overall appearance of the flow along the IEF channels seems consistent with a siphon flow model. We investigated the association of the IEF with the photospheric Evershed flow, but no obvious connection was found in our analysis. We also analysed the effect of the IEF on moving magnetic features (MMF) selected near and away from IEF channels. MMFs moved radially outward with velocities in the 0.2–1 km/s range, with no apparent association with the IEF. We concluded that the plasma flows supported by magnetic field lines in the chromospheric superpenumbral canopy are not associated with low-laying magnetic field lines underneath, hosting Evershed flow or MMFs.