Frequent Occurrence of High‐Speed Local Mass Downflows on the Solar Surface
| Autor: | Bruce W. Lites, Kiyoshi Ichimoto, Saku Tsuneta, Toshifumi Shimizu, Theodore D. Tarbell, Richard A. Shine, Yukio Katsukawa, Y. Suematsu, Masahito Kubo, Shin’ichi Nagata |
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| Rok vydání: | 2008 |
| Předmět: |
Convection
Physics sunspots Sunspot Astrophysics (astro-ph) FOS: Physical sciences Sun: photosphere Astronomy and Astrophysics Astrophysics Polarization (waves) Magnetic flux Magnetic field Space and Planetary Science Excited state Sun: atmospheric motions Physics::Space Physics Astrophysics::Solar and Stellar Astrophysics Supersonic speed Sun: magnetic fields Excitation |
| Zdroj: | The Astrophysical Journal. 680:1467-1476 |
| ISSN: | 1538-4357 0004-637X |
| Popis: | We report on new spectro-polarimetric measurements with simultaneous filter imaging observation, revealing the frequent appearance of polarization signals indicating high-speed, probably supersonic, downflows that are associated with at least three different configurations of magnetic fields in the solar photosphere. The observations were carried out with the Solar Optical Telescope onboard the {\em Hinode} satellite. High speed downflows are excited when a moving magnetic feature is newly formed near the penumbral boundary of sunspots. Also, a new type of downflows is identified at the edge of sunspot umbra that lack accompanying penumbral structures. These may be triggered by the interaction of magnetic fields sweeped by convection with well-concentrated magnetic flux. Another class of high speed downflows are observed in quiet sun and sunspot moat regions. These are closely related to the formation of small concentrated magnetic flux patches. High speed downflows of all types are transient time-dependent mass motions. These findings suggest that the excitation of supersonic mass flows are one of the key observational features of the dynamical evolution occurring in magnetic-field fine structures on the solar surface. 26 pages, 10 figures, accepted for publication on the Astrophysical Journal |
| Databáze: | OpenAIRE |
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