Solar wind origin of terrestrial water

The origin of the Earth water reserves during the evolution of the planet is one of the big miracles in geophysics. Common explanations are storage of water in the Earth mantle at a time when the crust had not yet formed and depositing of water by comets during the time of late heavy bombardement. Both explanations have different problems - especially when comparing with the evolution of Mars and Venus. Here we discuss the possible role of hydrogen collected from the solar wind by the early Earth magnetosphere. While the water production by solar wind capture is very small today it may have been significant during the first billion years after planetary formation because solar wind was much stronger at that time and Earth magnetospheric configuration may have been different. We estimate that the contribution of solar wind hydrogen to the Earth water reserves can be up to 10% when we assume a that the Earth dipole acted as a collector and early solar wind was 1000 times stronger than today. We can not even exclude that solar wind hydrogen was the main contributor to Earth water reserves

Capture of solar wind alpha-particles by the Martian atmosphere

International audienceIntegration along He test-particle trajectories in the self-consistent electromagnetic fields generated by threedimensional hybrid simulations of the solar wind/Mars interaction is used to evaluate the removal of solar wind alpha-particles due to charge-exchange processes with neutral species of the Martian exosphere. The total removal rate of solar wind He ions, transformed into either singly ionised or neutral helium, is equal to 6.7 x 10**23 s-1, which corresponds approximately to 30solar a-particles through the planetary cross-section. The deposition rate of helium neutral atoms, created by double electronic capture on exospheric oxygen, impacting the exobase, and penetrating below where it can be trapped, is about 1.5 x 10**23 s-1. That means an important contribution of the solar wind source to the helium balance of the Martian atmosphere. The implantation of the solar helium into the Martian atmosphere shows an asymmetry related to the orientation of the motional electric field of the solar wind

The MSA (Mass Spectrum Analyzer) onboard Bepi Colombo MMO (Mercury Magnetospheric Orbiter)

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The MSA (Mass Spectrum Analyzer) onboard Bepi Colombo MMO (Mercury Magnetospheric Orbiter)

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The MSA (Mass Spectrum Analyzer) onboard Bepi Colombo MMO (Mercury Magnetospheric Orbiter)

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BepiColombo and Solar Orbiter VGAM2 : Coordinated observations of the ion composition and total ion flux in the induced magnetosphere of Venus

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