[inquest]

There is talk of restoring Mars's mag field so there would be a shield against solar storms, but this is associated with restoring Mars's atmosphere somehow.

Your hypothesis. The truth may well be the reverse, namely that the presence of a magnetic field may provide the necessary protection for an atmosphere to form.

[RightWhale]

Right, but we don't know. My point is that we assume it is earth's core generating the magfield. The atmosphere could be doing it. All you need is dipoles. A quart of free electrons would create a field as strong as earth's gravity, so the atmosphere is plenty to generate the magfield.