Detection of Supergranulation Alignment in Polar Regions of the Sun by Helioseismology

Abstract

We report on a new phenomenon of `alignment' of supergranulation cells in the polar regions of the Sun. Recent high-resolution datasets obtained by the Solar Optical Telescope onboard the Hinode satellite enabled us to investigate supergranular structures in high-latitude regions of the Sun. We have carried out a local helioseismology time-distance analysis of the data, and detected acoustic travel-time variations due to the supergranular flows. The supergranulation cells in both the north and south polar regions show systematic alignment patterns in the north-south direction. The south-pole datasets obtained in a month-long Hinode campaign indicate that the supergranulation alignment property may be quite common in the polar regions. We also discuss the latitudinal dependence of the supergranulation cell sizes; the data show that the east-west cell size decreases towards higher latitudes.

arXiv comment7 pages, 5 figures. Accepted for publication in ApJ Letters. Minor modifications in figures and texts

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Cited by in corpus (2)

• Helioseismology with Solar Orbiter
• Investigating toroidal flows in the Sun using normal-mode coupling