fibrils


fibrils

(fÿ -brălz) Predominantly horizontal strands of gas in the solar lower chromosphere – typically 11 000 km long and 725–2200 km wide – that are visible (in the monochromatic light of certain strong Fraunhofer lines) as dark absorption features against the brighter disk. They form an ordered pattern in and around active regions, where they tend to be aligned in the direction of the localized magnetic field. The overall configuration of fibrils is stable over a period of several hours, though an individual fibril has a lifetime of only 10–20 minutes.