Astronomy and Astrophysics – Astrophysics – Solar and Stellar Astrophysics
Scientific paper
2009-10-12
Astronomy and Astrophysics
Astrophysics
Solar and Stellar Astrophysics
4 pages, 3 figures, A&A Letter, accepted (final version)
Scientific paper
Recent progress in instrumentation enables solar observations with high resolution simultaneously in the spatial, temporal, and spectral domains. We use such high-resolution observations to study small-scale structures and dynamics in the chromosphere of the quiet Sun. We analyze time series of spectral scans through the Ca II 854.2nm spectral line obtained with the CRISP instrument at the Swedish 1-m Solar Telescope. The targets are quiet Sun regions inside coronal holes close to disc-centre. The line core maps exhibit relatively few fibrils compared to what is normally observed in quiet Sun regions outside coronal holes. The time series show a chaotic and dynamic scene that includes spatially confined "swirl" events. These events feature dark and bright rotating patches, which can consist of arcs, spiral arms, rings or ring fragments. The width of the fragments typically appears to be on the order of only 0.2", which is close to the effective spatial resolution. They exhibit Doppler shifts of -2 to -4 km/s but sometimes up to -7 km/s, indicating fast upflows. The diameter of a swirl is usually of the order of 2". At the location of these swirls, the line wing and wide-band maps show close groups of photospheric bright points that move with respect to each other. A likely explanation is that the relative motion of the bright points twists the associated magnetic field in the chromosphere above. Plasma or propagating waves may then spiral upwards guided by the magnetic flux structure, thereby producing the observed intensity signature of Doppler-shifted ring fragments.
der Voort Luc Rouppe van
Wedemeyer-Böhm Sven
No associations
LandOfFree
Small-scale swirl events in the quiet Sun chromosphere does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Small-scale swirl events in the quiet Sun chromosphere, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Small-scale swirl events in the quiet Sun chromosphere will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-464951