Frequent Occurrence of High-speed Local Mass Downflows on the Solar Surface - AstrophysicsReport as inadecuate

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Abstract: We report on new spectro-polarimetric measurements with simultaneous filterimaging observation, revealing the frequent appearance of polarization signalsindicating high-speed, probably supersonic, downflows that are associated withat least three different configurations of magnetic fields in the solarphotosphere. The observations were carried out with the Solar Optical Telescopeonboard the {\em Hinode} satellite. High speed downflows are excited when amoving magnetic feature is newly formed near the penumbral boundary ofsunspots. Also, a new type of downflows is identified at the edge of sunspotumbra that lack accompanying penumbral structures. These may be triggered bythe interaction of magnetic fields sweeped by convection with well-concentratedmagnetic flux. Another class of high speed downflows are observed in quiet sunand sunspot moat regions. These are closely related to the formation of smallconcentrated magnetic flux patches. High speed downflows of all types aretransient time-dependent mass motions. These findings suggest that theexcitation of supersonic mass flows are one of the key observational featuresof the dynamical evolution occurring in magnetic-field fine structures on thesolar surface.

Author: T.Shimizu, B.W.Lites, Y.Katsukawa, K.Ichimoto, Y.Suematsu, S.Tsuneta, S.Nagata, M.Kubo, R.A.Shine, T.D.Tarbell


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