NASA’s MAVEN Illuminates New Understanding of Auroras at Mars

This illustration depicts charged particles from a solar storm stripping away charged particles of Mars’ atmosphere, one of the processes of Martian atmosphere loss studied by NASA’s MAVEN mission. NASA/GSFC NASA MAVEN (Mars Atmosphere and Volatile Evolution) mission scientists have uncovered a key puzzle piece in understanding certain types of auroras on Mars, finding that they form in a similar way to Earth-based auroras. Results published Thursday in Nature Communications show the same mechanism that circulates and catapults charged particles into Earth’s atmosphere is happening at Mars on much smaller scales because of differences in the two planets’ magnetic fields.

The MAVEN spacecraft, in orbit around Mars, experienced a loss of signal with ground stations on Earth on Dec. 6, 2025. On June 3, NASA declared the mission had concluded after finding the spacecraft to be unrecoverable.

However, data from the mission is still being used to inform NASA science and future missions to Mars. When the Sun’s magnetic field lines get close to Earth’s magnetosphere, the large magnetic bubble protecting the planet, they can reconnect and inject energy and mass throughout Earth’s magnetosphere and magnetotail , ultimately firing electrons back into the atmosphere to generate Earth’s auroras. This process, called the Dungey cycle, drives electrical currents, accelerates charged particles that create auroras, and controls the circulation of plasma in Earth’s magnetosphere and ionosphere.

This new study shows that a miniature version of the Dungey cycle is happening over Mars’ strong crustal magnetic fields, which gives scientists a better look into the physics of Martian auroras. “We knew that magnetic reconnection was happening at Mars but did not expect it to be like the Dungey cycle,” said Shaosui Xu, lead author of the study and associate research physicist at the Space Sciences Laboratory at the University of California, Berkeley. Mars does not have a global magnetic field like Earth.

Earth’s magnetic field is created by our planet’s churning core, while Mars has numerous miniature magnetospheres that arise from intensely magnetized crust scattered around the planet. These regions were formed around 4 billion years ago when lava cooled in the presence of Mars’ ancient global magnetic field, which has since disappeared due to intense solar wind stripping the planet’s atmosphere. The MAVEN mission has observed highly localized auroras over these crustal fields, similar to Earth’s auroras at the poles, but it wasn’t until now that scientists could fully understand the physics of how they form.

The study used several instruments aboard the MAVEN spacecraft to build up a picture of the Dungey-like behavior: the Magnetometer and Solar Wind Electron Analyzer instruments, which were used to determine the magnetic configuration and derive electrical currents, and the STATIC (Suprathermal and Thermal Ion Composition) instrument, which was used to measure plasma flows in the ionosphere. “We really pushed the limit of STATIC to get the data we needed,” said Xu. ” The realization that a Dungey-like cycle was happening within these crustal magnetic fields answered the question of how the electrons were being energized to create the auroras.