Comment Re:Planetary magnetic field (Score 1) 98
While Venus and Mars have no magnetosphere to protect the atmosphere from solar winds, photoionizing radiation (sunlight) and the interaction of the solar wind with the atmosphere of the planets causes ionization of the uppermost part of the atmosphere. This ionized region, in turn induces magnetic moments that deflect solar winds much like a magnetic field.
See: https://en.wikipedia.org/wiki/Atmospheric_escape#Significance_of_solar_winds
I would also think that solar winds would be a steady source of hydrogen atoms as it consists largely of hydrogen ions (also known as protons (H+)). Once in the atmosphere they would capture electrons to become stable hydrogen. This has been detected on the moon for instance (only 10% of the solar wind ions deflect off the moon and 90% become embedded in the lunar surface and become neutral hydrogen atoms by picking up free electrons). Since Venus has very little water (approximately
If we're going to get into the world of fantasy, I would think that setting up a sun-facing device that created a weak magnetic field far enough out in front of Venus that was strong enough to slow the rain of protons but not deflect them, could result in Venus gradually building up a water canopy . . .