Magnetic flows surge at the Sun’s south pole, defying solar physics models
Data from ESA’s Solar Orbiter, published on November 5, 2025, in The Astrophysical Journal Letters, show magnetic fields at the Sun’s south pole flowing toward the pole at 10–20 m/s (33–66 ft/s). The discovery overturns decades of theory about how the Sun’s magnetic field circulates.
The magnetic network on the solar surface leaves imprints in the chromosphere above. In images of this region taken by Solar Orbiter's Extreme Ultraviolet Imager (EUI), these imprints appear as bright spots. This processed EUI image of the Sun's south pole (indicated by the white dot) is constructed by combining eight days of observations from March this year. This image shows the tracks of the bright spots. Due to the Sun's rotation, they are seen as elongated, bright arcs. Credit: ESA & NASA / Solar Orbiter / EUI-Team
For the first time, scientists have tracked magnetic flows at the Sun’s south pole directly. Observations from ESA’s Solar Orbiter reveal that surface magnetic structures migrate toward the pole at speeds between 10–20 m/s (33–66 ft/s).
The discovery challenges a core assumption of solar physics: that the Sun’s global magnetic conveyor belt slows nearly to a stop near the poles. Instead, the plasma and magnetic field lines appear to surge northward in both hemispheres, maintaining momentum even at the highest latitudes.
Researchers describe the finding as a breakthrough in understanding how the Sun’s magnetism regenerates. The magnetic network, long invisible near the poles, can now be tracked as it drifts and accumulates.
“The supergranules at the poles act as a kind of tracer. They make the polar component of the Sun’s global, eleven-year circulation visible for the first time,” said Lakshmi Pradeep Chitta, research group leader at the Max Planck Institute for Solar System Research (MPS) and first author of the study.
This poleward migration explains how magnetic energy is redistributed before the next solar cycle begins. The results give physicists their first direct clue about how polar magnetic fields form, strengthen, and reverse.
Why this changes how we see the solar cycle
The Sun’s activity follows a rhythm that peaks every 11 years, marked by flaring sunspots and eruptions. This rhythm is controlled by immense plasma circulations within the solar interior and at its surface.
At the surface, charged gas flows carry magnetic field lines from the equator toward the poles. Deep inside, other flows return that energy toward the equator. Together, these movements create a vast engine known as the solar dynamo, responsible for generating the Sun’s magnetism.
The newly observed poleward speeds mean that the upper part of this magnetic conveyor moves faster than once believed. That could influence how quickly the Sun’s magnetic poles reverse and how intense the next cycle will be.
“To understand the Sun’s magnetic cycle, we still lack knowledge of what happens at the Sun’s poles. Solar Orbiter can now provide this missing piece of the puzzle,” said Sami Solanki, MPS Director and co-author of the study.
If polar flux reaches its destination faster, it could shorten the interval between solar maxima or alter the strength of upcoming cycles. The results add urgency to improving solar forecasting, crucial for predicting space weather events that can disrupt satellites and power grids.
How Solar Orbiter revealed what Earth could not see
The Solar Orbiter mission, a collaboration between ESA and NASA, was launched in February 2020. In March 2025, the spacecraft left the plane where all planets orbit and reached a 17° inclination above the ecliptic, giving it a direct line of sight toward the solar south pole.
During an eight-day observing campaign from March 16–24, Solar Orbiter’s Extreme Ultraviolet Imager (EUI) and Polarimetric and Helioseismic Imager (PHI) collected high-resolution data. These instruments captured both visible and ultraviolet images, measuring plasma motion, magnetic field strength, and the structure of the chromosphere above the photosphere.
The processed images showed the south pole studded with bright arcs and streaks—traces of magnetic elements being carried toward the pole. Each bright point corresponds to a concentration of magnetic field embedded in the Sun’s plasma.
From these data, scientists reconstructed how those points drifted over time. Their average migration speed, between 10–20 m/s (33–66 ft/s), surprised researchers. The magnetic field, long assumed sluggish near the poles, was in fact moving almost as quickly as it does closer to the equator.
This was the first time any spacecraft directly mapped polar magnetic transport from above the solar limb, filling a gap that ground-based observatories could never reach.
Supergranules: the cellular engine beneath the flow
Beneath the smooth appearance of the solar surface lies a restless pattern of convection called supergranulation. Each supergranular cell is roughly 20 000–40 000 km (12 400–24 800 miles) wide and lasts about one to two days before dissolving.
Within these vast cells, hot plasma rises from below, spreads outward horizontally, and cools as it sinks along the boundaries. The outward flow sweeps magnetic field lines toward the edges, creating the solar magnetic network—a web of magnetic concentrations outlining each cell.
At high latitudes, the team found that these supergranular patterns are similar in size and motion to those at lower latitudes. That means convection behaves uniformly across the entire solar surface, even near the poles.
The researchers used autocorrelation analysis of PHI velocity data to measure the scale of these structures. The results revealed characteristic cell diameters of 20 000–40 000 km (12 400–24 800 miles), confirming that supergranulation persists unchanged even in the polar environment.
Because the bright points in the chromosphere trace the movement of the underlying cells, they serve as natural trackers for the magnetic field’s migration. Their collective motion revealed the large-scale poleward transport observed in the study.
From plasma noise to confirmed flow
The research team considered whether the apparent migration might result from random turbulence rather than an organized current. A single supergranule’s surface flow reaches about 300–500 m/s (980–1 640 ft/s), but the chaotic motion of thousands of such cells tends to cancel out when averaged across large regions.
After analyzing eight days of observations, the team estimated the residual noise caused by this randomness to be about 6–10 m/s (20–33 ft/s)—well below the measured 10–20 m/s (33–66 ft/s) poleward drift. This difference rules out turbulence as the main cause.
The scientists also examined the influence of global oscillations and inertial modes—large-scale waves rippling through the Sun’s interior. These produce surface velocities of less than 5 m/s (16 ft/s), again too small to explain the observed trend.
This convergence of evidence confirmed that the flow is real, not an artifact. It represents a sustained, coherent motion of the Sun’s magnetic network toward the pole.
The result gives scientists a tangible measurement for the surface component of the meridional circulation, the flow pattern that carries magnetic flux toward the poles and returns it deep inside toward the equator.
What this means for future solar research
The data provide only a brief eight-day snapshot of solar behavior, yet they mark the first direct observation of polar magnetic migration. Future Solar Orbiter campaigns will repeat these measurements over longer intervals and at higher inclinations to see whether the flow speed changes as the Sun approaches magnetic reversal.
If the high-latitude transport remains fast throughout the cycle, it could alter our understanding of how the solar dynamo operates. The magnetic flux that accumulates at the poles eventually reverses direction, setting the stage for the next cycle. How quickly it builds up determines the pace and power of solar activity.
These findings also support the design of future dedicated polar missions, which could orbit the Sun at steep angles to map the full three-dimensional structure of its magnetic field.
“Our observations provide a new strategy for designing future campaigns that can answer remaining questions about the solar poles,” said Chitta. “The Solar Orbiter high-latitude campaigns mark the beginning of a new era in exploring the Sun’s polar regions.”
For now, the Solar Orbiter’s brief yet revealing glance has opened the door to solving one of solar physics’ oldest mysteries: how the star that powers Earth renews its magnetic heartbeat.
References:
1 Sun: First Glimpse of Polar Magnetic Field in Motion – MPS – November 5, 2025
2 Supergranulation and Poleward Migration of the Magnetic Field at High Latitudes of the Sun – Lakshmi Pradeep Chitta et al. – The Astrophysical Journal Letters – November 5, 2025 – https://iopscience.iop.org/article/10.3847/2041-8213/ae10a3 – OPEN ACCESS
I’m a science journalist and researcher at The Watchers, contributing to the Epicenter edition, where I cover peer-reviewed scientific research and emerging discoveries across Earth and space sciences. With a background in astronomy and a passion for environmental science, I’ve worked in shark and coral conservation in Fiji, conducting reef and shark-behavior research, contributing to mangrove restoration, and earning PADI Open Water and Coral Reef Certifications. I bring a blend of scientific rigor and storytelling to illuminate the discoveries shaping our planet and beyond.
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