Chromospheric fibrils
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Chromospheric fibrils above an active region
Swedish 1-m Solar Telescope
When observed in the H-alpha spectral line, the chromosphere reveals a very complex structure made up of elongated fibrils having different lengths and orientations. They are believed to trace magnetic field lines in the chromosphere. The longest fibrils are nearly horizontal and connect sunspots or plage regions of opposite polarity, often spanning large separations. They are rather static. Also, there are shorter, more vertical fibrils rooted in active region plage that show impressive dynamics, with swaying and rotational motions, and jets that push chromospheric plasma upwards. Both types of fibrils reveal the full complexity of the solar chromosphere, but we still do not know much about their properties, origin, and relation to the chromospheric magnetic field. The dynamics of the short fibrils, however, is consistent with the driver being photospheric oscillations that leak into the chromosphere through inclined magnetic structures. At chromospheric heights, they develop into shocks and produce their characteristic jet-like behavior.
The movie shows dramatic examples of dynamic fibrils and jets in active regions. The observations were taken near the core of the H-alpha line with the SOUP instrument at the Swedish 1-m Solar Telescope. Sometimes the images get a bit blurred because of turbulence in the Earth's atmosphere. During the sequence, a relatively large jet (called H-alpha surge) launches material to higher layers and then decays, showing very rapid changes and fine structure during its entire evolution.
To download the movie, click HERE
Movie credit: Michiel van Noort and Luc Rouppe van der Voort (ITA, University of Oslo)
Text credit: Luis Bellot Rubio (IAA-CSIC)
Source: SST Galleries