Solar prominence

In solar physics, a prominence, sometimes referred to as a filament, is a large plasma and magnetic field structure extending outward from the Sun's surface, often in a loop shape. Prominences are anchored to the Sun's surface in the much brighter photosphere, and extend outwards into the solar corona. While the corona consists of extremely hot plasma, prominences contain much cooler plasma, similar in composition to that of the chromosphere. Like the corona, solar prominences are only visible to the naked eye during a total solar eclipse. 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. Some prominences may give rise to coronal mass ejections. Exact mechanism of prominence generation is an ongoing target of scientific research. A typical prominence extends over many thousands of kilometers; the largest on record was estimated at over 800,000 km (500,000 mi) long, roughly of solar radius.