Solar plasma blobs under a microscope

Although filaments remain stable for extended periods of time, they may become activated by events occurring in their vicinity. Dr. Julius Koza, from the Astronomical Institute of the Slovak Academy of Sciences (AISAS, Slovakia), writes about what happens then.




The solar atmosphere is like a colorful garden harboring manifold plasma structures with sizes ranging from hundred of thousands kilometers down to the resolution limit of current large solar telescopes of about 150 kilometers. Most of them are of magnetic nature. In loop-like magnetic confinements plasma can aggregate into vast cloud-like structures called prominences observed at the solar limb. We call them filaments if seen in projection on the disk where they appear dark against bright background due to denser and cooler plasma absorbing the background radiation. Filaments remain stable for extended periods of time, but may become activated for example by a solar flare occurring in a vicinity of filament.

The movie shows such a dynamic filament observed by the Swedish Solar Telescope on La Palma (Canary Islands, Spain) on 14 May 2016. This wing-like filament was activated by a flare which occurred sooner close to the adjacent sunspot at the right side of the image. Vigorous dynamics of the activated filament induced fragmentation of the filament plasma into a shower of tiny plasma blobs with a typical size of 300 - 500 km apparent at the tips of the filament. One of them, identified by the arrow and the contours, was examined with an aim to infer its plasma parameters. They are shown in the colored sub-panels identifying the zoomed-in blob by the contours. These parameters allow estimating the plasma density of the blob, its mass and also the lower limit of the filament's magnetic field.

The European Solar Telescope, a new 4-meter class solar telescope to be built in the Canary Islands, will be capable of delivering superb microscopic observations of these tiny plasma blobs which may provide clues for answering big questions of solar physics. The high resolution of EST will be essential for achieving this goal.

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