Something New On the Sun: SDO Spots a Late Phase in Solar Flares

The sun's surface dances. Giant loops of magnetized solar material burst up, twist, and fall back down. Some erupt, shooting radiation flares and particles out into space. Forced to observe this dance from afar, scientists use all the tools at their disposal to look for patterns and connections to discover what causes these great explosions. Mapping these patterns could help scientists predict the onset of space weather that bursts toward Earth from the sun, interfering with communications and Global Positioning System (GPS) signals.

Analysis of 191 solar flares since May 2010 by NASA's Solar Dynamics Observatory (SDO) has recently shown a new piece in the pattern: some 15 percent of the flares have a distinct "late phase flare" some minutes to hours later that has never before been fully observed. This late phase of the flare pumps much more energy out into space than previously realized.

"We're starting to see all sorts of new things," says Phil Chamberlin, deputy project scientist for SDO at NASA's Goddard Space Flight Center in Greenbelt, Md. "We see a large increase in emissions a half-hour to several hours later, that is sometimes even larger than the original, traditional phases of the flare. In one case on November 3, 2010, measuring only the effects of the main flare would mean underestimating the amount of energy shooting into Earth's atmosphere by 70 percent."