Solar flares are often preceded by distinctive ‘sparks’, a new study points out. Smaller disturbances may occur over regions where an explosion may occur. Scientists hope that early detection of the ‘sparks’ will help predict when the next explosion will occur.
Solar flares are sudden, powerful bursts of energy and particles that occur in active regions of the Sun. They have a direct impact on what we see on Earth: the solar wind they release can produce northern lights and interfere with radio communication, and in extreme cases, even threaten astronauts and cause local power outages. The results, published in The Astrophysical Journal, could help astronomers predict where and when a solar flare will occur.
Sparks over active regions
A team of scientists from the NorthWest Research Associates (NWRA) research institute in Colorado looked at images of active regions of the Sun collected by the Solar Dynamics Observatory. NASA (SDO). The data came from eight years of follow-up. The authors studied a large sample of active areas using dedicated statistical methods.
The analysis showed that over regions where flares could occur, the Sun very often produces small flares. These small disturbances are located in our star’s corona, the outermost part of the Sun’s atmosphere. The ultraviolet images released with the study show what the same active region of NOAA AR 2109 looks like on the day before the flare (left) and on a “quiet” day (right). The lower images, on the other hand, show changes in background brightness over the same periods – black and white patches indicate high activity, and gray color – low variability.
“Sparks” before a solar flare (left) and the same area on a calm day (right)NASA/SDO/AIA/Dissauer et al. 2022
Predicting space weather
Scientists hope that the results of the study will provide a better understanding of the processes occurring in the active regions of the Sun. So far, only activity occurring in the lower layers of the solar atmosphere, such as the photosphere and chromosphere, has been studied in this respect.
“The information stored in the corona is completely different from that in the photosphere,” explains KD Leka of the NWRA, lead author of the study. ‘Our results can help us determine which active regions may flare up soon and which will remain calm.’
According to Karen Dissauer, co-author of the study, the data obtained can be used to develop new tools for predicting solar flares.
“Combining all the information from the Sun’s surface to the corona should allow us to more accurately predict when and where solar flares will occur,” he explains.
X1-class solar flare, October 2, 2022NASA/SDO
Main photo source: NASA/SDO