What is it that keeps the solar wind from blowing the atmosphere away, Gorilla Glue?
The magnetosphere protects the planet from charged particles. The ionosphere protects it from radiation.
https://www.quora.com/Are-the-solar-winds-stripping-away-Earths-atmosphere-and-if-so-at-what-rate
Solar wind stripping has probably been overestimated as a mechanism for atmospheric loss. It’s true that Mars has no magnetic field and it now has a very thin atmosphere, but it’s also true that Venus has a much weaker field than Earth’s field and it has a very dense atmosphere.