Question

Several planets in our solar system have a magnetosphere. Describe what is required, in general, for a magnetosphere to exist (not just Earth). Also comment on what you see as the impact to us if we had no magnetosphere.

Answer 1

The formation of a magnetosphere requires that the dipolar field is strong enough for the obstacle effective size to be larger (Dp > 20λi) than ion scales. In this case, a bow shock, magnetosheath, and magnetospheric system are driven, and the flow is modified far upstream.