Solar Orbiter traces magnetic switchback to its birthplace in the Sun's corona

New study pinpoints origin of solar wind structures for the first time

By LineZotpaper

Published21 October 2026

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A serendipitous encounter by the European Space Agency's Solar Orbiter has allowed scientists to trace a giant magnetic switchback directly back to the Sun's corona, resolving a long-standing debate about where these kinks in the solar magnetic field form. The findings, published in Nature Astronomy, show that the plasma inside the switchback originated in an ultra-hot closed magnetic loop near a coronal hole, consistent with the process of interchange reconnection.

Switchbacks are violent kinks in the Sun's magnetic field that affect the flow of the solar wind, the supersonic stream of charged particles that bathes the entire solar system. NASA's Parker Solar Probe has detected large numbers of them, but their origin had been unclear. The two leading theories were that they form in deep space due to turbulence within the solar wind itself, or in the Sun's extremely hot corona.

The breakthrough came on March 2, 2022, when Solar Orbiter was cruising at about half the Earth-Sun distance. Its instruments detected a major switchback, with elevated readings lasting about 90 minutes. Given the spacecraft's speed (30 to 40 km/s) and the switchback's speed relative to it (450 to 460 km/s), the radial size of the structure was estimated at about 2.75 million kilometres, about six times the Earth-Moon distance and 3.5 times the Sun's own radius.

During that time, the Heavy Ion sensor on Solar Orbiter recorded an increase in oxygen and carbon ions that had been stripped of their electrons, along with a decrease in helium relative to expected levels. In the hot lower reaches of the Sun's atmosphere, heavy ions are stripped of their electrons; once they move into open space, the temperature drops and the ions are preserved in that state. The data indicated the plasma had been baked at over one million degrees Celsius, most likely in the corona.

Researchers led by Jesse T. Coburn cross-referenced the data with observations from the Solar Dynamics Observatory at the same time. They mapped the plasma back to a closed magnetic loop near a coronal hole on the Sun. Coronal holes are darker, cooler regions where magnetic fields stretch into interplanetary space. The plasma clearly formed in a closed loop, leading the team to conclude the switchback was launched by interchange reconnection, where an arc of the loop encounters an open magnetic field line and snaps, slingshotting superheated gas into space.

The team also noted a discrepancy: the particles within the switchback did not travel straight, as would be expected from a simple slingshot, but instead behaved in sync with magnetic field lines, resembling an Alfven wave. This suggests the switchback, once launched, is governed by wave dynamics as well as the initial reconnection event.

Analysis

Why This Matters

Switchbacks influence the solar wind, which affects space weather and can disrupt satellite communications and power grids on Earth.
Pinpointing their origin helps solar physicists understand how the corona heats and accelerates the solar wind, a long-standing mystery.
The hybrid reconnection-wave explanation provides a more complete model for how magnetic energy is released and transported through the solar system.

Background

For years, scientists have debated where magnetic switchbacks come from. The Parker Solar Probe, which flies closer to the Sun than any other spacecraft, has spotted them in abundance but could not determine whether they were created near the Sun or formed later in interplanetary space. The Solar Orbiter, equipped with instruments that measure heavy ion charge states, offered a way to trace the plasma's thermal history. The March 2022 encounter was the first time a switchback could be linked to a specific feature on the Sun's surface.

Key Perspectives

Researchers (Jesse T. Coburn and co-authors): The data strongly point to a coronal origin via interchange reconnection, with the switchback's evolution also governed by Alfven wave dynamics. This settles a key question in heliophysics. Advocates of the turbulence theory: Some scientists have argued that switchbacks could form spontaneously in the solar wind through wave-wave interactions or shear instabilities. The new evidence does not rule out that some switchbacks form in deep space, but it confirms that at least one major switchback originated in the corona. Critics and skeptics: The study is based on a single event. It remains to be seen whether all switchbacks have the same origin or whether multiple formation mechanisms are at play. Future observations by both Solar Orbiter and Parker Solar Probe will be needed to generalise the finding.

What to Watch

Whether Solar Orbiter encounters additional switchbacks whose heavy ion composition can be analysed to confirm the pattern.
Parker Solar Probe's upcoming perihelia, which may provide complementary data on switchback structure closer to the Sun.
Further theoretical work on how interchange reconnection and Alfven wave dynamics interact to produce the observed magnetic kinks.

Sources

Solar Orbiter Traces Giant Magnetic Switchbacks Directly Back to the Sun · Universe Today

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10 claims in this story checked against 1 source: 6 supported.

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SupportedSolar Orbiter traced a giant magnetic switchback directly back to the Sun’s corona.Universe Today: “that serendipitous encounter allowed them to track the switchback back to its birthplace in the solar corona for the first time.”
Partly supportedThe new study pinpointed the origin of solar-wind structures for the first time.Universe Today: “that serendipitous encounter allowed them to track the switchback back to its birthplace in the solar corona for the first time.”
Partly supportedThe finding resolved a long-standing debate about where switchbacks form.Universe Today: “The breakthrough that helped answer this question began as a serendipitous encounter on March 2, 2022”
Not in the sourcesSolar Orbiter is the European Space Agency’s spacecraft.
SupportedThe plasma inside the switchback originated in a hot closed magnetic loop near a coronal hole, and the team concluded the switchback was launched by interchange reconnection.Universe Today: “Since the plasma was clearly formed in a closed loop, the researchers concluded that the switchback itself was launched by a process known as an interchange reconnection.”
SupportedThe encounter occurred on March 2, 2022, when Solar Orbiter was about halfway between Earth and the Sun.Universe Today: “on March 2, 2022, when Solar Orbiter was cruising through the solar system at roughly half the distance between Earth and the Sun.”
SupportedThe switchback’s radial size was estimated at about 2.75 million kilometres, roughly six Earth-Moon distances and 3.5 times the Sun’s radius.Universe Today: “that would put the radial size of the switchback itself at around 2.75 million kilometers - about 6 times the distance from the Earth to the Moon, and even 3.5 times the radii of the Sun itself.”
SupportedThe particle data showed increased stripped oxygen and carbon ions and reduced helium; the plasma was most likely heated to over one million degrees Celsius in the corona.Universe Today: “it seemed pretty clear that the plasma it encountered in the switchback had been baked at over one million degrees Celsius - most likely in the Sun’s extremely hot corona.”
Partly supportedResearchers led by Jesse T. Coburn cross-referenced Solar Orbiter data with Solar Dynamics Observatory observations from the same time and mapped the plasma to a closed loop near a coronal hole.Universe Today: “To confirm their suspicion, they cross referenced data from the Solar Dynamics Observatory that happened at the same time Solar Orbiter had crossed the switchback, and mapped the plasma back to a closed magnetic loop near a feature called a coronal hole on the Sun.”
SupportedThe particles behaved in sync with magnetic field lines, resembling an Alfvén wave, suggesting wave dynamics governed the switchback after launch as well as reconnection.Universe Today: “Instead, they seem to behave in sync with magnetic field lines, creating a feature that looks similar to an Alfven wave”