mioara mandea - research planetary

Mars magnetic field

Mars is a fascinating planet, as many of the processes that have occurred on Earth also happened there. Moreover, the more we explore Mars at a detailed level, the more it reveals itself as a unique world. A revolution in our understanding came with NASA's MGS spacecraft, which showed for the first time that Mars has a magnetic field. However, unlike Earth, Mars shows no evidence of a core-generated magnetic field. When comparing the magnetic spectra of Earth and Mars, we see a stark contrast: Mars' magnetic field is dominated by an internal, static field of lithospheric origin, whereas Earth's magnetic field is primarily driven by its core.

The Martian lithospheric magnetic field is about an order of magnitude stronger than Earth's lithospheric field, when measured at comparable altitudes (approximately 400 km above the surface). The most intense magnetic sources are found in the Cimmeria region, where fields exceeding 1500 nT were detected near Mars' periapsis at an altitude of 100 km. This discovery opens up exciting possibilities for comparing the magnetic signatures of impact craters on Mars, Earth, and the Moon, a topic I have been actively researching.

Mars' global magnetic field existed only during the first few hundred million years of its history, when the planet's molten core conditions were favorable for generating a magnetic dynamo. But why did the Martian magnetic field disappear? What is the spatial coherence of Mars' magnetization across different regions or time periods? What factors explain the order of magnitude difference between the lithospheric magnetic fields of Earth and Mars? These fundamental questions also touch on Mars' interaction with the solar wind. For example, what is the magnetic structure of Mars' regional "magnetospheres," and how is it influenced by factors like solar zenith angle and solar wind conditions? Can we detect any signatures of magnetic reconnection between the interplanetary magnetic field and the Martian crustal field? A more detailed mapping of Mars' magnetic field could provide critical insights into these questions.

Mercury magnetic field

Although Mercury's magnetic field is thought to be a miniature version of Earth's, it is still not fully understood. Its origin is likely internal, but there is ongoing debate about other potential sources, such as remanent magnetization in an inhomogeneous crust, an induced planetary-scale magnetic field, or thermoelectric currents. On average, Mercury’s field appears to be a dipole, in contrast to the Moon and Mars, which lack a global magnetic field but have localized anomalies tied to specific rock deposits.hich lack such a field field, but have local magnetic fields centred on different rock deposits.

The MESSENGER and BepiColombo missions, both equipped with magnetometers, will provide crucial data to characterize Mercury's magnetic field in greater detail from orbit. These missions will measure the field’s strength and examine how it varies with position and altitude.

Bepi Colombo launched in 2018 is now scheduled to arrive at the tiny and little-studied planet in November 2026.Upon arrival, it will map the magnetic field and help resolve the debate over its origin. If a core origin for Mercury’s magnetic field is confirmed, it would provide the first definitive evidence of a liquid core on another terrestrial planet. This discovery would also allow us to estimate the size of Mercury's core. As a Co-Investigator on the MERMAG payload, I have been involved in preparing for this mission to ensure we achieve these key scientific goals and further our understanding of Mercury's magnetic field.

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