An international team of researchers including astrophysicists from Oregon State University has confirmed a 19-year-old theory about the formation of solar flares. Their findings, compared to the rapid movements of a famous cartoon predator, offer new insights into this powerful solar phenomenon.
Understanding solar flares is critical to predicting space weather and minimizing its impact on technology and human activities, explains Vanessa Polito of the OSU College of Science.
"Solar flares can release huge amounts of energy, 10 million times greater than the energy released by volcanic eruptions," Polito said. "Flares and related coronal mass ejections can drive beautiful auroras, but they can also severely impact our space environment, disrupt communications, cause harm to astronauts and space satellites, and impact power grids here on Earth."
The phenomenon of "sliding" reconnection of the Sun's magnetic field lines - a term inspired by Wile E. Coyote's mad dash as he chased the RoadRunner - was observed with NASA's Interface Region Imaging Spectroradiometer (IRIS).
IRIS is a satellite used to study the solar atmosphere. Observations of tiny yet brilliant features in the Sun's atmosphere moving at unprecedented speeds - thousands of kilometers per second - are opening the door to a deeper understanding of the production of solar flares - the most powerful explosions in the solar system.
Guillaume Aulanier of the Paris Observatory, one of the collaborators on this study, proposed the concept of sliding reconnection in 2005.
But measuring the speed of a solar flare's core has been difficult, Polito said. Flare cores are small, bright regions within larger flare belts that mark locations where magnetic fields reconnect. These regions are called footpoints, where intense heat and energy releases occur.
However, a recently designed high-confidence observation program (which captures images approximately every two seconds) has revealed the sliding motion of the core moving at speeds of up to 2,600 kilometers (1,600 miles) per second.
"The tiny, bright features observed by IRIS trace the rapid motion of individual magnetic field lines that slide along the solar atmosphere during flares," said Polito, deputy principal investigator of the IRIS mission. "Flares and magnetic reconnection are phenomena that occur in all stars and with different astrophysical objects throughout the universe, such as pulsars and black holes. On the Sun, our closest star, we can study them in great detail, as our study demonstrates."
When a solar flare occurs, the Sun's atmosphere suddenly emits intense radiation by rapidly releasing accumulated magnetic energy. The energy output of a flare is equivalent to the simultaneous explosion of millions of hydrogen bombs, covering the entire electromagnetic spectrum from radio waves to gamma rays.
Flares are often associated with massive ejections of plasma, a high-temperature gas in which electrons are separated from atomic nuclei, from the corona, a phenomenon known as a coronal mass ejection. Flares can last anywhere from a few minutes to a few hours.
Compiled from /scitechdaily
DOI:10.1038/s41550-024-02396-4