Scientists map complete energy spectrum of solar high-energy protons near Mars

Reuters Events SMR and Advanced Reactor 2025

Scientists map complete energy spectrum of solar high-energy protons near Mars
by Simon Mansfield
Sydney, Australia (SPX) Nov 26, 2024

Scientists have achieved a major milestone in Martian space research by constructing the first complete energy spectrum of high-energy solar protons during a solar eruptive event. This effort sheds light on the radiation environment around Mars and has important implications for future Mars exploration.

The research was a collaborative effort involving the University of Science and Technology of China, the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS), the Lanzhou Institute of Physics, and the University of Kiel in Germany. Their findings have been published as a cover article in 'Geophysical Research Letters'.

Solar energetic particle (SEP) events, triggered by solar eruptions, are among the most intense space weather phenomena. They lead to sudden surges in high-energy charged particles, posing risks to spacecraft and astronauts. Unlike Earth, Mars lacks a global magnetic field and has a thin atmosphere, making its surface especially susceptible to high-energy particles and their secondary interactions. Understanding these SEP events is critical for ensuring the safety of future Mars missions.

In November 2021, China's Tianwen-1 orbiter entered its scientific orbit around Mars, equipped with the Mars Energy Particle Analyzer (MEPA). This advanced instrument is capable of measuring particle energies ranging from 2 to 100 MeV. Its observations have significantly advanced the study of high-energy protons in Martian space.

On February 15, 2022, MEPA captured data from a particularly intense SEP event. This event was also detected by the European Space Agency's Trace Gas Orbiter (TGO), NASA's Mars Atmosphere and Volatile Evolution Orbiter (MAVEN), and the Curiosity rover on the Martian surface. This marks the first SEP event simultaneously recorded by such a wide array of detectors around and on Mars.

The researchers integrated data from multiple detectors to produce the proton energy spectrum, with Tianwen-1 and MAVEN providing low- and medium-energy data and Curiosity contributing high-energy proton observations. Simulations of particle transport through the Martian atmosphere further complemented the dataset.

By combining these observations and simulations, the team successfully developed a comprehensive proton energy spectrum covering a range from 1 to 1000 MeV. They used the spectrum to calculate radiation doses in Martian orbit and on its surface. These results aligned closely with actual dose measurements, validating both the reliability of MEPA's data and the accuracy of their radiation transport models.

This study underscores the value of coordinated radiation monitoring on Mars and provides a framework for studying similar space weather phenomena in the future.

Research Report:The 2022 February 15 Solar Energetic Particle Event at Mars: A Synergistic Study Combining Multiple Radiation Detectors on the Surface and in Orbit of Mars With Models