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arXiv 2012.043082020-12-08astro-ph.SR

Alfvenic Perturbations in a Sunspot Chromosphere Linked to Fractionated Plasma in the Corona

D. Baker, M. Stangalini, G. Valori, D. H. Brooks, A. S. H. To, L. van Driel-Gesztelyi, P. Demoulin, D. Stansby, D. B. Jess, S. Jafarzadeh

备注：: 14 pages, 6 figure, accepted by ApJ on 15 November 2020
DOI：: 10.3847/1538-4357/abcafd

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In this study, we investigate the spatial distribution of highly varying plasma composition around one of the largest sunspots of solar cycle 24. Observations of the photosphere, chromosphere, and corona are brought together with magnetic field modelling of the sunspot in order to probe the conditions which regulate the degree of plasma fractionation within loop populations of differing connectivities. We find that in the coronal magnetic field above the sunspot umbra, the plasma has photospheric composition. Coronal loops rooted in the penumbra contain fractionated plasma, with the highest levels observed in the loops that connect within the active region. Tracing field lines from regions of fractionated plasma in the corona to locations of Alfvenic fluctuations detected in the chromosphere shows that they are magnetically linked. These results indicate a connection between sunspot chromospheric activity and observable changes in coronal plasma composition.

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