Abstract Details
| Name: Debiprasad Choudhary Affiliation: California State University Northridge Conference ID: ASI2019_100 Title : Properties of the Inverse Evershed Flow around Sunspots Authors and Co-Authors : Debi Prasad Choudhary, California State University, Northridge Christian Beck, National Solar Observatory, Boulder Abstract Type : Poster Abstract Category : Sun and the Solar System Abstract : The properties of the Inverse Evershed Flow (IEF) around a sunspot in the Active Region 11809 were studied using spectropolarimetric observations in photospheric Fe I lines at 1565 nm and the chromospheric Ca II IR line at 854.2 nm acquired at the NSF’s Dunn Solar Telescope. The data were recorded with the Spectropolarimeter for Infrared and Optical Regions (SPINOR) and adaptive optics under excellent seeing conditions. The photospheric and chromospheric Stokes profiles were inverted using the SIR and CAISAR inversion codes, respectively, to obtain the stratifications of temperature, velocity and magnetic field over the line forming regions of the solar atmosphere. We find that the flow fibrils that harbor the IEF make an angle of 30°– 60° to the local vertical, tilting away from the umbra. The temperature near the down-flow points in and near the penumbra is enhanced by 200 K at log τ ~ -2 and up to 2000 K at log τ ~ - 6 compared to the quiet Sun, without any signature in the low photosphere. The flow speed reduces from 5-15 km / s to about zero over a distance of less than 1 Mm at the down-flow points. Our results are consistent with a critical, i.e., sonic, or supersonic siphon flow along super-penumbral flux tubes in which accelerating plasma abruptly attains subsonic velocity through a standing shock at upper photospheric heights in or near the penumbra. In this paper, we present magnetic and thermodynamic properties of the flow channels. |