New study uncovers unexpected interaction between Mars and the solar wind

Scientists of the Swedish Institute of Space Physics (IRF) in Kiruna and Umeå University find that under certain conditions the induced magnetosphere of Mars can degenerate. The findings are presented in a new study published in Nature.

An induced magnetosphere is formed when a planet lacks an internal magnetic field and instead the atmosphere of the planet interacts directly with the solar wind. The solar wind is a stream of charged particles from the sun with an embedded magnetic field.

The scientists have been using computer models and observations from scientific instruments, such as IRF's Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3), onboard the ESA spacecraft Mars Express and NASA's spacecraft MAVEN, both of which orbit around Mars.

"When the solar wind proton flows align with the magnetic field of the solar wind, the induced magnetosphere of Mars will degenerate. Such a degenerate magnetosphere will affect how much atmosphere is lost from Mars to space," says the lead author Qi Zhang, Ph.D. student at IRF and Umeå University.

The ASPERA-3 instrument measures the fluxes of ions, electrons and neutral atoms in space around Mars. During more than 20 years in orbit around the planet, ASPERA-3 has made a number of interesting observations of Mars, including continuous measurements of the ion outflow from the planet.