NASA Scientists Trace Solar Energetic Particles To Their Source

Humans working and living in space face potential dangers and challenges that are unheard of here on earth. One of the challenges posed by the Sun to astronauts working in space are particles known as solar energetic particles or SEPs. These tiny particles move at nearly the speed of light and have the ability to reach Earth from the Sun in under an hour. The particles also have the ability to destroy electronics in spacecraft and pose a health risk for astronauts.

The onset of SEPs is extraordinarily hard to predict, partly because scientists don't know exactly where they originate from on the Sun. However, a new study has been able to trace SEP bursts back to the sun and has shed light on the answer to this question for the first time. Scientist Stephanie Yardley says that researchers have been able to pinpoint the specific sources of these energetic particles for the first time.

Yardley believes that understanding the source regions and physical processes that produce SEPs could lead to improved forecasting for the events. Researchers know SEPs can emanate from the sun in any direction, and merely observing one in space is difficult. Observing these particles in space is one of the main functions of the NASA Heliophysics System Observatory.

Scientists split SEP events into two broad categories: impulsive and gradual. Impulsive events happen after solar flares and are bright flashes on the sun produced by abrupt magnetic eruptions. Gradual SEPs a longer-lived and can sometimes last for days. They are typically generated in large swarms, making them a more significant risk to astronauts or satellites.

Gradual SEPs are pushed from behind by coronal mass ejections, large plumes of solar material billowing through space like a tidal wave. Researchers traced gradual SEP events from January 2014 back to their origins on the sun. They were able to show that the events had a specific fingerprint, meaning a different mix of particles than is typically found in the solar wind. The team says the SEPs had somehow broken free from the strong magnetic loops connected to the sun at both ends. The discovery has raised new questions for future work, but pinpointing their source is a crucial first step.