Solar Orbiter has identified the Sun’s dual “engines” for superfast electrons. The European Space Agency’s Solar Orbiter mission has identi...
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| Solar Orbiter has identified the Sun’s dual “engines” for superfast electrons. |
Solar flares, the sudden bursts of energy from the Sun’s surface, can hurl electrons into space at near-light speed, reaching Earth in under an hour. Meanwhile, CMEs act as giant magnetic shockwaves, sweeping up and accelerating particles over longer periods. For decades, researchers debated which of these phenomena dominated particle acceleration. The new observations reveal that both mechanisms are at play, operating in tandem to fuel the Sun’s particle storms.
One of the breakthroughs came from Solar Orbiter’s ability to study particle events close to their origin, before the electrons became scattered and diluted in interplanetary space. Instruments on board tracked the timing and energy levels of these particles, finally explaining why electrons sometimes appeared late relative to the flare that triggered them. In many cases, the delay was caused by CME-driven shocks injecting fresh electrons into the solar wind long after the initial flare.
This discovery is more than just a triumph of heliophysics—it has direct implications for space weather forecasting. Solar energetic particles pose serious risks to astronauts, satellites, and power grids on Earth. By better understanding when and how these dangerous electrons are accelerated, scientists can improve models that predict their arrival. This could provide earlier warnings to shield spacecraft electronics, reroute polar flights, and protect crews aboard missions to the Moon and Mars.
The findings also demonstrate the unique capabilities of Solar Orbiter, which was launched in 2020 as a joint mission of ESA and NASA. Its orbit brings it closer to the Sun than any previous European spacecraft, allowing it to measure magnetic fields, particle streams, and extreme ultraviolet emissions in unprecedented detail. Future close encounters will give researchers even sharper views of the solar poles and magnetic activity cycles, further unraveling the mysteries of our star.
Solar Orbiter carries ten state-of-the-art instruments that work in synergy. Its suite of imagers captures the Sun’s surface and corona, while in-situ sensors measure the solar wind and high-energy particles directly. For the first time, scientists can link what they see on the Sun with the particles detected around the spacecraft, connecting cause and effect in near real time. This dual capability has been essential in uncovering the role of both flares and CMEs in particle acceleration.
Another milestone came when the mission captured images of tiny magnetic structures—nicknamed “campfires”—dotting the Sun’s surface. These small-scale eruptions may also contribute to particle acceleration and the heating of the solar corona, which remains hundreds of times hotter than the solar surface below. Understanding whether these miniature flares work together with larger eruptions is now a key focus for researchers.
Compared to earlier missions such as SOHO or STEREO, Solar Orbiter offers closer, sharper, and more dynamic observations. When combined with NASA’s Parker Solar Probe, which dives even deeper into the Sun’s corona, scientists are piecing together a multi-perspective map of solar activity. The collaboration between these spacecraft is providing an unprecedented “stereo vision” of the Sun, helping researchers see how local eruptions grow into massive space-weather events that spread across the solar system.
For Earth, the stakes are high. Solar storms have the power to disrupt GPS navigation, communication systems, and even knock out electrical grids, as seen during the 1859 Carrington Event. As humanity prepares for long-duration missions to the Moon and Mars, accurate space weather forecasting will be critical to astronaut safety. Solar Orbiter’s discoveries are paving the way for predictive models that could give astronauts hours of warning to take shelter from radiation storms.
Space physicists believe this is just the beginning. By combining Solar Orbiter’s results with data from Parker Solar Probe, ground-based observatories, and upcoming missions such as ESA’s Vigil, scientists aim to build a comprehensive picture of how solar storms are born, evolve, and spread. Such knowledge will be crucial for humanity’s next era of exploration, as astronauts venture deeper into space where Earth’s protective magnetic shield no longer reaches.
In the words of ESA researchers, the Sun is “a laboratory of extremes.” With every orbit, Solar Orbiter is showing us that its engines—flares and CMEs—are not rival forces, but partners in powering the streams of energetic particles that shape our cosmic neighborhood. The better we understand them, the safer our journey into the solar system will be.
