New observations from NASA’s Parker Solar Probe show how Sun’s plasma that is released after a solar flare can accelerate and pile up solar energetic particles generating dangerous radiation conditions.
NASA’s Parker Solar Probe approaching the Sun. Image credit: NASA’s Scientific Visualization Studio.
“We’re getting some of the earliest observations from this mission to the Sun on how the coronal mass ejection — the Sun’s release of plasma and energy — builds up particles released after solar flare events,” said Professor Nathan Schwadron, a researcher in the Space Science Center at the University of New Hampshire and the Department of Astrophysical Sciences at Princeton University.
“Because energetic particles are accelerated near the sun, by flying closer and getting a better look we are able to observe the beginning of the energization process and see them actually start to pile up like snow that piles up in front of a snowplow.”
“Instead of an actual snowplow, it is the coronal mass ejections released from the sun that cause the buildup of this material in space.”
Professor Schwadron’s team observed solar energetic particle events from April 18, 2019 to April 24, 2019, when two active regions near the Sun’s equator became highly unstable, releasing a number of flares followed by coronal mass injections.
They saw the complex interplay between the flares, particle populations and coronal mass injections causing the pre-accelerated particles that are created by these solar events to get trapped and pile up.
The study highlights a new phase of the energization process that is critical for the formation of radiation hazards.
Snapshots showing a model of the April 20, 2019 coronal mass injections (CME) released at 01:25 UTC and propagating out to NASA’s Parker Solar Probe. Panels show the evolution of the CME through the inner heliosphere at different stages of the CME’s propagation to the spacecraft. Left panels show modeled densities and right panels show the speed structure from the 3D model. Image credit: Schwadron et al, doi: 10.3847/1538-4365/ab5527.
“We have known that these high-energy particles are energized in this region, but the missing link was how these particles buildup in the fronts of coronal mass ejections,” Professor Schwadron said.
“It’s like imagining a room filled with bouncing tennis balls and asking how did they get there?”
“The particles become so highly energized that they move at almost the speed of light and, as a result, can pose hazards in the form of harmful radiation that cause health issues for astronauts and damage electronic equipment in space.”
The findings are published in the Astrophysical Journal Supplement Series.
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N.A. Schwadron et al. 2020. Seed Population Preconditioning and Acceleration Observed by the Parker Solar Probe. ApJS 246, 33; doi: 10.3847/1538-4365/ab5527
