Fibrils in Ca II K
Abstract
High spatial resolution observations have revealed that fibril-like structures are a ubiquitous feature of the solar chromosphere. They are observed in most chromospheric lines, e.g., H-? and Ca II IRT. Until recently, there have been no reports of these structures in the Ca II H and K lines. Instead, these lines have revealed a hazy, uniform chromosphere and only in the highest resolution images have there been any indications of fibril structures.
We present high spatial resolution Ca II K observations from the Swedish Solar Telescope which show that fibrils are a prevailing feature in regions where the bulk of the signal is chromospheric. Based on the cotemporal continuum and nearly cotemporal magnetic field observations it is clear that the fibril foot points originate from photospheric magnetic concentrations. The fibrils share many characteristics, e.g. lifetime and dynamics, with fibrils observed in other spectral lines. They are also found to play an important role in the dynamics: in the plage they channel low frequency waves into the chromosphere while in the more quiet regions the highly inclined fibrils form a multi-layer canopy that suppresses oscillations from below.- Publication:
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European Solar Physics Meeting
- Pub Date:
- September 2008
- Bibcode:
- 2008ESPM...12.2.51P