doi:10.1038/nindia.2016.39 Published online 22 March 2016
By analysing data from a sun-pointing spacecraft, astrophysicists have gained new insights into how extreme ultraviolet waves and charged particles emanate from the Sun1. These insights will help scientists better understand and predict such solar phenomena that have the potential to disrupt satellite communication and spacecraft navigation.
During solar eruptions, the extended outer atmosphere of the Sun―the corona―ejects large clouds of charged particles and harmful ultraviolet waves into space. This phenomenon, known as coronal mass ejection, ejects up to 10,000,000,000 tons of plasma at speeds as high as 1,600,000 kilometres an hour.
To investigate such ejections, the researchers analysed data from the Solar Dynamics Observatory, a spacecraft launched by NASA. This analysis revealed that extreme ultraviolet waves are strongly associated with solar eruptive events such as flares, coronal mass ejections and solar filaments.
The scientists probed solar filaments, which are eruptive events in the corona, and found that the filaments are 100 times cooler and denser than their surrounding environment. They also found that eruptions of filaments generate fast- and slow-moving extreme ultraviolet waves that move away from the Sun.
“Understanding extreme ultraviolet waves is important as they could be a source of solar energetic particles that could potentially hamper the activities of satellites,” says Ramesh Chandra, one of the researchers.