Researchers have identified evidence suggesting that the Sun, akin to Earth, may possess swirling polar vortices. Unlike those observed on other planets in our solar system, these solar vortices are generated by strong magnetic fields.
The findings, published on November 11 in the Proceedings of the National Academy of Sciences, enhance the understanding of the Sun's magnetic behavior and improve predictions related to solar cycles and space weather.
Polar vortices are defined as rotating columns of air, well-documented on Earth and other celestial bodies. On Earth, they influence climate patterns by trapping cold air near the poles, only allowing it to surge towards lower latitudes when the vortices weaken.
Mausumi Dikpati, the lead author of the study and an atmospheric physicist at the National Center for Atmospheric Research in the United States, notes that this phenomenon has been observed on Jupiter, where NASA's Juno mission captured images of eight tightly packed polar vortices at the northern pole and five at the southern pole. The Cassini spacecraft also revealed a hexagonal vortex at Saturn's northern pole.
Dikpati states, “While polar vortices are common across celestial bodies, the Sun features a unique environment of plasma and strong magnetic fields that sets it apart.”
Despite this groundbreaking discovery, direct observation of the Sun's poles has yet to occur. Current research relies on complex computer simulations to understand potential activities in these enigmatic regions.
The research team utilized simulations to reveal a possible pattern of solar polar vortices, providing critical insights into how the Sun's magnetic field influences its structure. “No one can definitively state what happens at the Sun's poles, but this new research presents an exciting glimpse into what we may find,” Dikpati remarked.
In the simulations, a ring of polar vortices forms around 55 degrees latitude—approximately equivalent to the Arctic Circle on Earth—as the Sun approaches its peak solar activity, a point in the solar cycle where its magnetic poles shift.
During this “flow towards the poles,” magnetic fields of opposite polarity move towards the Sun's poles, interacting with the ring of vortices and reshaping it. At the peak of the solar cycle, this ring narrows, leaving a few vortices near the poles, which then disappear and reappear in subsequent cycles.
Dikpati believes this discovery offers new insights that could assist in determining optimal timing for future solar missions. She points out that polar vortices are only visible during specific stages of the solar cycle, making the timing of observations critical.
This research represents a significant advancement in solar studies and paves the way for understanding fundamental questions surrounding solar magnetism and its cycles.
Through missions like the Solar Orbiter spacecraft, a joint project between NASA and the European Space Agency, scientists hope to monitor the Sun's poles and validate models predicting polar vortices.
Such missions could provide an opportunity to confirm the existence of polar vortices and link solar magnetic activity to broader phenomena, such as space weather that may impact Earth, according to a press release from the National Center for Atmospheric Research.
The results underscore the necessity for multi-point observations of the Sun, allowing scientists to test their hypotheses and refine predictions regarding solar behavior.