Scientists at the Southwest Research Institute (SwRI), led by Dr. Keiichi Ogasawara, have discovered that helium pickup ions play a crucial role in generating solar energetic particles (SEPs). These findings, published in May 2025, enhance our understanding of space weather and its impact on astronauts and spacecraft.
Helium pickup ions are formed when neutral atoms from interstellar space are ionized by solar ultraviolet radiation. These ions are then caught by the solar wind's magnetic fields. The study reveals that during coronal mass ejections (CMEs), these ions accelerate to high speeds, becoming SEPs. Data from NASA's STEREO mission was used to track the velocity of these ions during CME events.
The research indicates that helium ions move at speeds twice as fast as the solar wind, even during quiet solar periods. This makes them prime candidates for acceleration during interplanetary shocks. Understanding this acceleration process is vital for predicting and mitigating the radiation risks posed by solar storms, ultimately safeguarding space missions and astronauts.