In December 2023, scientists looking at Mars data found something completely unexpected – the observation of a never-before-seen atmospheric effect in the Red Planet’s atmosphere. Using instruments aboard NASA’s MAVEN (Mars Atmosphere and Volatile Evolution) mission, scientists identified a phenomenon occurring in Earth’s magnetosphere, where charged particles are squeezed along magnetic structures called flux tubes, like toothpaste coming out of a tube. This so-called Zwan–Wolf effect assists in the deflection of the solar wind around Earth and has been observed and studied there for decades. Now, a new study published in Nature Communications provides the first comprehensive observation of the same effect in the atmosphere of Mars.
“While examining the data, I suddenly noticed some very interesting changes,” said Christopher Fowler, a research assistant professor at West Virginia University in Morgantown and lead author of the study. “I never would have guessed it would have such an impact, because it has never been seen in a planet’s atmosphere before.”
The Zwan–Wolf effect was first discovered in 1976, and so far it has only been observed in the magnetospheres of planets, not their atmospheres. Unlike Earth, Mars is not protected by the global magnetic field, which affects its interaction with the solar wind and space weather. In this new study, the Zwann-Wolf effect was observed in the ionosphere – within the Martian atmosphere below 200 km – which contains significant numbers of electrically charged particles. The data showed that these charged particles were being squeezed and distributed around the atmosphere of Mars.
Although Mars has an induced magnetosphere, a magnetic field generated by the solar wind interacting with the Martian ionosphere, it can change significantly in size and shape with large solar wind and space weather events. This is what Fowler and his team saw in MAVEN data when a large solar storm hit Mars. Based on their findings, the Zwan–Wolf effect may occur continuously in the Martian ionosphere, but at a level undetected by MAVEN’s instrument. The impact of the space weather phenomenon appears to have magnified the effect, allowing scientists to see it in the data.
Early on, Fowler and his team encountered some interesting-looking fluctuations in magnetic field measurements as the spacecraft flew through the atmosphere. To explain this, they studied observations made by several instruments on MAVEN, including measurements of the charged particle environment in the ionosphere. His detectives uncovered even more strange and interesting features in the data. After ruling out several other possibilities, the team was able to identify the culprit as the Zwaan–Wolf effect, which explained all the features they were observing.
“No one expected that this effect could happen even in the atmosphere,” Fowler said. “That’s what makes it even more exciting. It introduces interesting physics that we haven’t discovered yet and a new way in which the Sun and space weather can change the dynamics in the Martian atmosphere.”
Understanding the Zwann-Wolf effect at Mars will expand our understanding of how space weather affects the planet and provide new insight into how this effect might occur on similar unmagnetized bodies such as Venus and Saturn’s moon Titan. Such observations also highlight the importance of understanding how large space weather events can alter the atmosphere on and around the Red Planet and potentially impact properties on or near Mars.
“It is essential to know how space weather interacts with Mars,” said Shannon Curry, MAVEN principal investigator and research scientist at the Atmospheric Space Physics Laboratory at the University of Colorado Boulder. “The MAVEN team is making new discoveries with our dataset and finding these links between our host star and the red planet.”
The MAVEN spacecraft launched in November 2013 and entered Mars orbit in September 2014. The mission’s goal is to explore the planet’s upper atmosphere, ionosphere, and interactions with the Sun and the solar wind in order to detect the loss of the Martian atmosphere to space. Understanding atmospheric loss gives scientists information about the Red Planet’s atmosphere and climate, liquid water, and the history of the planet’s habitability. In orbit around Mars, the MAVEN spacecraft experienced a loss of signal with ground stations on Earth on December 6, 2025. In February 2026, NASA launched an anomaly review board to assess the probable current position of the spacecraft and the likelihood of its recovery.
MAVEN is part of the mission NASA’s Mars Exploration Program Portfolio. of mission The principal investigator is based in the Atmospheric and Space Physics Laboratory at the University of Colorado Boulder, who is also responsible for managing science operations and public outreach and communications. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the MAVEN mission. Lockheed Martin Space built the spacecraft and is responsible for mission operations. NASA’s Jet Propulsion Laboratory in Southern California provides navigation and Deep Space Network support.
by willow reed
Laboratory for Atmospheric and Space Physics, University of Colorado Boulder
media Contact:
Karen Fox / Alana Johnson
Headquarters, Washington
240-285-5155/202-672-4780
karen.c.fox@nasa.gov / alana.r.johnson@nasa.gov
sarah frazier
Goddard Space Flight Center, Greenbelt, MD.
sarah.frazier@nasa.gov
