Scientists analyzing data from NASA’s MAVEN spacecraft have identified a previously unseen atmospheric phenomenon on Mars. The effect, known as the Zwan‑Wolf phenomenon, was first observed in Earth’s magnetosphere in 1976 and is responsible for squeezing charged particles along magnetic flux tubes. In a study published in *Nature Communications*, researchers reported the first clear evidence of this effect occurring within the Martian ionosphere.

The discovery emerged when lead author Christopher Fowler and his team noticed irregular fluctuations in the magnetic field measurements taken by MAVEN as it orbited the planet. By cross‑checking these anomalies against data from multiple instruments—particularly those monitoring ionospheric charged particles—they ruled out alternative explanations and confirmed that the disturbances matched the signature of the Zwan‑Wolf effect.

Unlike Earth, Mars lacks a global magnetic field, but its ionosphere can generate an induced magnetosphere that fluctuates with solar wind pressure. The team found that a recent solar storm amplified the effect, allowing MAVEN’s instruments to detect the otherwise subtle squeezing of charged particles below 200 km altitude. The researchers suggest that the Zwan‑Wolf effect may be a constant, yet undetected, feature of Mars’ upper atmosphere, becoming visible only during intense space‑weather events.

“This is the first time the Zwan‑Wolf effect has been observed in a planetary atmosphere,” said Fowler. “It opens up new avenues for understanding how solar activity shapes the dynamics of Mars’ upper atmosphere and could have implications for other unmagnetized bodies such as Venus and Titan.”

The finding underscores the importance of monitoring space weather impacts on Mars, especially as future missions plan to deploy assets in orbit and on the surface. MAVEN, launched in 2013 and operating since 2014, continues to provide crucial insights into atmospheric loss processes that have shaped the planet’s climate history.

The study highlights how even subtle plasma physics can have far‑reaching effects on planetary environments and demonstrates the value of long‑term, high‑precision observations from orbiting platforms.