NASA's Cosmicopia -- Sun - Solar Activity

A solar flare is an enormous explosion in the solar atmosphere. It results in sudden bursts of particle acceleration, heating of plasma to tens of millions of degrees, and the eruption of large amounts of solar mass. Flares are believed to result from the abrupt release of the energy stored in magnetic fields in the zone around sunspots.

There are two types of flares: impulsive and gradual. Impulsive flares accelerate mostly electrons, with some protons. They last minutes or hours and the majority appear near the solar equator. Impulsive flares occur at a rate of about 1000 per year during solar maximum.

Gradual flares accelerate electrons, protons, and heavy ions to near the speed of light, and the events tend to last for days. They occur mainly near the poles of the Sun and happen about 100 times per year.

This acceleration of solar flare particles to extremely high energies involves all the different elements in the solar atmosphere. Ions of elements such as carbon, nitrogen, oxygen, neon, magnesium, silicon, and iron, excited in this way, end up in solar cosmic rays, also called solar energetic particles (SEPs).

More about solar flares from the NASA GSFC Laboratory for Astronomy and Solar Physics...

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Solar Flares in the News:

July 28, 2009: Space aged: 10 spacecraft from decades past that are still ticking -- ISEE-3/ICE (1978) -- Scientific American
May 27, 2009: The phantom torso returns -- Science@NASA
December 15, 2008: Solar flare surprise -- NASA
August 22, 2008: Some solar flares may be caused by dark matter -- New Scientist
June 21, 2008: 2012: No killer solar flare -- Universe Today
June 2, 2008: What did EV Lac? -- HEAPOW
May 19, 2008: Small star gets Swift reaction with unprecedented flare -- University of Maryland
May 6, 2008: A super solar flare -- Science@NASA
April 18, 2008: Solar flares set the sun quaking -- ESA
April 2, 2008: Hinode: Source of the slow solar wind and superhot flares -- ESA
April 2, 2008: 'Focused' solar explosions get hotter -- NASA GSFC
February 8, 2008: NASA calls for suggestions to rename future telescope mission -- NASA GSFC
January 31, 2008: New discovery on magnetic reconnection to impact future space missions -- Science Daily
December 19, 2007: Solar-like star flares up -- Astronomy.com
November 6, 2007: An X class flare region on the Sun -- APOD
August 27, 2007: Flares from Sun's far side may affect space weather of inner planets -- Science Daily
August 22, 2007: Hinode helps unravel long-standing solar mysteries -- Eurekalert
April 24, 2007: A massive explosion on the Sun -- Science@NASA
April 4, 2007: Researchers find Global Positioning System is significantly impacted by powerful solar radio burst -- NOAA News
March 30, 2007: Sun burp blasted ozone layer in 1859 -- Australian Broadcasting Company

Solar flare news from 2006 and earlier

BASICS .. COSMIC RAYS .. SUN .. SPACE WEATHER