Solar prominence

In solar physics, a prominence, sometimes referred to as a filament,[a] is a large plasma and magnetic field structure extending outward from the Sun's surface, often in a loop shape.

Prominences form over timescales of about a day and may persist in the corona for several weeks or months, looping hundreds of thousands of kilometers into space.

Today, due to a better understanding of the diversity of these phenomena, most of these are classified separately, and the word prominence is primarily used to refer to larger and cooler features.

[13] Prominences form in magnetic structures known as filament channels where they are thermally shielded from the surrounding corona and supported against gravity.

The magnetic field making up the filament channel is predominantly horizontal, pointing in the same direction on both sides of the PIL (see § Chirality).

The spine defines the upper main body of a prominence and is generally in the form of a vertical sheet that diverges towards the photosphere at both ends.

Spines and barbs are both composed of thin threads that trace the magnetic field similar to chromospheric fibrils.

[7] Above filament channels lie overarching magnetic arcades which can extend from 50,000 to 70,000 km (31,000 to 43,000 mi) into the corona.

Above these arcades, the closed coronal magnetic field may extend radially outward, forming what is known as a helmet streamer.

Models must be able to explain the formation of the filament channel and its hemisphere-dependent chirality, as well as the origin of the dense plasma that makes up the prominence core.