Recent findings from NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) mission have indicated that the Zwan-Wolf effect—a phenomenon previously believed to be exclusive to Earth’s magnetosphere, characterized by the compression of charged particles along magnetic field lines known as flux tubes, akin to squeezing toothpaste—is actively reshaping the upper atmospheric layers of the Red Planet.
An artistic representation of the Zwan-Wolf effect at Mars, as observed by NASA’s MAVEN mission. Image credit: LASP / CU Boulder.
“While scrutinizing the MAVEN data, I unexpectedly encountered some highly intriguing oscillations,” remarked Dr. Christopher Fowler, a researcher affiliated with West Virginia University.
“I would not have anticipated this particular phenomenon, given that it had never been documented within a planetary atmosphere prior to this discovery.”
The Zwan-Wolf effect was initially identified in 1976, and until this recent observation, its presence had only been confirmed within planetary magnetospheres, distinct from their atmospheric envelopes.
In contrast to Earth, Mars lacks a global magnetic field for protection, which significantly influences its interactions with the solar wind and broader space weather dynamics.
The MAVEN spacecraft detected the Zwan-Wolf effect within the Martian ionosphere, situated deep within the planet’s atmosphere below an altitude of 200 km, an area rich in electrically charged particles.
Although Mars possesses an induced magnetosphere—a magnetic field generated by the interaction of the solar wind with the Martian ionosphere—its dimensions and configuration can undergo substantial alterations in response to significant solar wind and space weather events.
This variability was precisely what Dr. Fowler and his collaborators observed in the MAVEN data during a powerful solar storm impacting Mars.
The researchers postulate, based on their findings, that the Zwan-Wolf effect might be a persistent feature of the Martian ionosphere, albeit typically at levels too subtle for MAVEN’s instruments to detect.
It appears that the intensity of the space weather event played a critical role in amplifying the effect, thereby enabling its observation in the gathered data.
Initially, the study’s authors noted anomalous fluctuations in magnetic field measurements as the spacecraft traversed the Martian atmosphere.
To elucidate these observations, they delved into data collected by multiple instruments aboard MAVEN, including those measuring the plasma environment within the ionosphere.
Their detailed investigation revealed further unusual and compelling characteristics within the data.
After eliminating alternative explanations, they concluded that the Zwan-Wolf effect was the most plausible cause, successfully accounting for all observed features.
“The possibility of this effect manifesting within an atmosphere was entirely unforeseen,” stated Dr. Fowler.
“This unexpected revelation is particularly exhilarating, as it unveils novel physical processes that have yet to be thoroughly explored and offers a fresh perspective on how solar activity and space weather can alter the dynamics of the Martian atmosphere.”
“Investigating the Zwan-Wolf effect on Mars will deepen our comprehension of the planet’s susceptibility to space weather and provide valuable insights into its potential occurrence on comparable celestial bodies lacking intrinsic magnetic fields, such as Venus and Saturn’s moon, Titan.”
“Observations of this nature underscore the critical importance of understanding how severe space weather events can instigate environmental transformations on and around the Red Planet, with potential implications for operational assets situated there or in its vicinity.”
“A robust understanding of space weather interactions with Mars is paramount,” emphasized Dr. Shannon Curry, MAVEN’s principal investigator and a researcher at the Laboratory for Atmospheric Space Physics at the University of Colorado Boulder.
“The MAVEN team continues to generate groundbreaking discoveries from our collected datasets, consistently identifying connections between our star and the Red Planet.”
The research endeavor was formally presented this week in the esteemed journal Nature Communications.
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C.M. Fowler et al. 2026. Detection of Zwan-Wolf effect in the ionosphere of Mars. Nat Commun 17, 4224; doi: 10.1038/s41467-026-72251-9
