MITRE - Y2K - Solar Flares

The following Y2K material has been kept available by MITRE for historical purposes only and has not been updated unless noted.

SOLAR FLARES

The "Solar Flare" is an explosive release of energy (both electromagnetic and charged particles) within a relatively small (but greater than earth-sized) region of the solar atmosphere. While the energy released during a flare is very substantial; it represents at most 1/100,000th of the total solar output. Consequently, daily lives on earth normally appear to be unaffected by solar flares. However, a flare's enhanced X-ray, EUV, radiowave, and particle emissions are sufficient to adversely impact radar, communications, and space systems operating in or through the near-Earth environment.

Flares are also one cause of "Eruptive Prominences or Disappearing Filaments", which are outward ejections of material previously suspended cloud-like in the solar atmosphere.

Filaments are ribbon-like features supported by magnetic fields in the sun's atmosphere; they are equivalent to clouds on Earth. Filaments have a higher density and lower temperature than the rest of the sun's atmosphere, and so appear dark when seen against the brighter solar background. However, when filaments are seen on the sun's limb, they appear as bright features against the dark of space, and are then called prominences.

A Coronal Mass Ejection is a huge cloud of ejected plasma from the solar corona into the interplanetary medium. They are often associated with eruptive prominences, suddenly disappearing filaments, and solar flares. CMEs accompany many large solar flares, but can also accelerate particles into space in the absence of a solar flare.

CMEs cause most large geomagnetic storms during the most active part of the solar cycle, about 72 hours after the eruption.

For further information directly related to Year 2000 issues, please contact Year2000@mitre.org

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Last modified: Thursday, 14-Feb-2008 09:21:04 EST