Vol 18, No 10 (2018) / Liu

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Manifestations of bright points observed in G-band and Ca II H by Hinode/SOT

Yan-Xiao Liu, Ning Wu, Jun Lin

Abstract

An algorithm was developed for identifying and tracking a magnetic bright point, or bright point (BP) for short, observed in both the photosphere (G-band) and chromosphere (Ca II H), as well as for pairing a photospheric BP (PBP) with its conjugate chromospheric BP (CBP). Two sets of data observed by Hinode/SOT in the quiet Sun near the disk center were analyzed. About 278 PBP-CBP pairs were identified and tracked. Lifetimes of both the PBPs and CBPs follow an exponential distribution with average lifetimes of 174 s and 163 s, respectively. We found that the differences in appearance time, in disappearance time and in lifetime of the two kinds of BPs all follow Gaussian distributions,which may indicate that the mechanisms of PBP and CBP formation/disintegration are different. However, the lifetimes of PBPs and CBPs are positively correlated with one another, with a correlation coefficient of 0.8. Furthermore, we calculated the horizontal displacement between the PBP and its conjugate CBP, which follows a Gaussian function with an average and standard deviation of (67.7 ± 38.5) km. We also calculated the amplitude of the flux tube shape change which might be caused by MHD waves propagating along the flux tube, and found that it follows an exponential distribution very well.

Keywords


Sun: photosphere — Sun: chromosphere — methods: observational — techniques: image processing

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DOI: https://doi.org/10.1088/1674–4527/18/10/125

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