Detection of opposite polarities in a sunspot light bridge: evidence of low-altitude magnetic reconnection |
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Authors: | Lokesh Bharti Thomas Rimmele Rajmal Jain S. N. A. Jaaffrey R. N. Smartt |
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Affiliation: | Department of Physics, University College of Science, Mohanlal Sukhadia University, Udaipur, 313001, India;US National Solar Observatory, Sunspot, Sacramento Peak, NM 88349, USA;Physical Research Laboratory (Department of Space, Govt. of India), Navrangpura, Ahmedabad, 380 009, India |
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Abstract: | A multiwavelength photometric analysis was performed in order to study the sub-structure of a sunspot light bridge in the photosphere and the chromosphere. Active region NOAA 8350 was observed on 1998 October 8. The data consist of a 100 min time series of 2D spectral scans of the lines Fe i 5576 Å, Hα 6563 Å, Fe i 6302.5 Å, and continuum images at 5571 Å. We recorded line-of-sight magnetograms in 6302.5 Å. The observations were taken at the Dunn Solar Telescope at US National Solar Observatory, Sacramento Peak. We find evidence for plasma ejection from a light bridge followed by Ellerman bombs. Magnetograms of the same region reveal opposite polarity in light bridge with respect to the umbra. These facts support the notion that low-altitude magnetic reconnection can result in the magnetic cancellation as observed in the photosphere. |
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Keywords: | Sun: chromosphere Sun: magnetic fields Sun: photosphere sunspots |
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