Chromospheric velocities of a C-class flare
Data(s) |
01/05/2011
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Resumo |
Aims. We use high spatial and temporal resolution observations from the Swedish Solar Telescope to study the chromospheric velocities of a C-class flare originating from active region NOAA 10969.<br/>Methods. A time-distance analysis is employed to estimate directional velocity components in Hα and Ca ii K image sequences. Also, imaging spectroscopy has allowed us to determine flare-induced line-of-sight velocities. A wavelet analysis is used to analyse the periodic nature of associated flare bursts.<br/>Results. Time-distance analysis reveals velocities as high as 64 km s-1 along the flare ribbon and 15 km s-1 perpendicular to it. The velocities are very similar in both the Hα and Ca ii K time series. Line-of-sight Hα velocities are red-shifted with values up to 17 km s-1. The high spatial and temporal resolution of the observations have allowed us to detect velocities significantly higher than those found in earlier studies. Flare bursts with a periodicity of ≈60 s are also detected. These bursts are similar to the quasi-periodic oscillations observed at hard X-ray and radio wavelength data.<br/>Conclusions. Some of the highest velocities detected in the solar atmosphere are presented. Line-of-sight velocity maps show considerable mixing of both the magnitude and direction of velocities along the flare path. A change in direction of the velocities at the flare kernel has also been detected which may be a signature of chromospheric evaporation. |
Identificador | |
Idioma(s) |
eng |
Direitos |
info:eu-repo/semantics/restrictedAccess |
Fonte |
Keys , P H , Jess , D B , Mathioudakis , M & Keenan , F P 2011 , ' Chromospheric velocities of a C-class flare ' Astronomy and Astrophysics , vol 529 , A127 , pp. 1-5 . DOI: 10.1051/0004-6361/201016320 |
Palavras-Chave | #/dk/atira/pure/subjectarea/asjc/3100/3103 #Astronomy and Astrophysics #/dk/atira/pure/subjectarea/asjc/1900/1912 #Space and Planetary Science |
Tipo |
article |