Detection of opposite polarities in a sunspot light bridge: evidence of low‐altitude magnetic reconnection

Monthly Notices of the Royal Astronomical Society (Impact Factor: 5.52). 04/2007; 376(3):1291 - 1295. DOI: 10.1111/j.1365-2966.2007.11525.x
Source: arXiv

ABSTRACT ABSTRACTA 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, H 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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