NASA MAVEN spots atmospheric effect on Mars

NASA said this week that its MAVEN spacecraft has detected the Zwan-Wolf effect in Mars’ atmosphere for the first time, a phenomenon previously observed in planetary magnetospheres rather than atmospheres. The finding came from data gathered in December 2023, when a large solar storm hit Mars, according to NASA and a study published in Nature Communications. Christopher Fowler, lead author of the study and a research assistant professor at West Virginia University, said he first noticed unusual “wiggles” in the magnetic-field data. The result gives scientists a new observation of how space weather can compress and redistribute charged particles around Mars. ### What exactly did MAVEN find in the Martian atmosphere? NASA said MAVEN identified the Zwan-Wolf effect in the Martian ionosphere, below 200 kilometers, where electrically charged particles are abundant. On Earth, the effect is associated with charged particles being squeezed along magnetic structures called flux tubes as the solar wind presses on a planet’s magnetic environment. (science.nasa.gov) The Nature Communications paper said the observations were made at an unmagnetized planet that lacks a global dipole magnetic field. NASA described the Mars detection as the first comprehensive observation of the effect in a planetary atmosphere. ### Why was Mars an unexpected place to see it? Mars does not have a global magnetic field like Earth’s, NASA said, and that is why the detection surprised the research team. (science.nasa.gov) Instead, the planet has an induced magnetosphere created by the interaction between the solar wind and the Martian ionosphere, and that structure can change shape during strong space-weather events. (nature.com) Christopher Fowler said he “would never have guessed it would be this effect,” because it had not previously been seen in a planetary atmosphere. NASA said the Zwan-Wolf effect was first identified in 1976 and had until now been observed in planetary magnetospheres, not atmospheres. ### What happened in December 2023 that made the signal visible? (science.nasa.gov) NASA said a large solar storm struck Mars in December 2023, and the event appears to have amplified the effect enough for MAVEN’s instruments to detect it. The agency said the same process may be occurring more regularly in the Martian ionosphere, but at levels too weak for MAVEN to measure under quieter conditions. (science.nasa.gov) The study linked the observation to changes in Mars’ induced magnetic environment during the storm. NASA said the data showed charged particles being squeezed and distributed around the atmosphere as the spacecraft passed through the region. ### Who made the discovery and how was it reported? NASA published the finding on May 18, 2026, and identified Fowler as lead author of the study. (science.nasa.gov) The paper was published in Nature Communications, and NASA’s account said the discovery came after researchers examined magnetic-field fluctuations in MAVEN data from December 2023. A social-media post by Elysia Segal helped draw wider attention to the result on May 19, after NASA’s publication. (science.nasa.gov) NASA’s MAVEN mission page says the orbiter, which entered Mars orbit on Sept. 21, 2014, is dedicated to understanding the Martian upper atmosphere and how the planet lost much of it over time. ### What comes next for MAVEN researchers? NASA said MAVEN’s broader mission is to study Mars’ upper atmosphere and its interaction with the Sun and solar wind. (science.nasa.gov) The agency said the new result could help researchers further examine how space-weather events affect the Martian ionosphere and atmospheric loss. That work will continue through MAVEN data analysis and follow-up studies tied to the Nature Communications paper. (science.nasa.gov)