Thanks, but
I'm still not convinced that the effect of the Moon's gravity might not be affecting the convection currents, and thus the magnetosphere.
It strikes me that the fluid dynamics of this are pretty complex (they must be modeled on a pretty powerful computer) and my gut feeling is that even a small input will lead to fairly startling results.
Thanks though.
(PS - I probably would have used a small "a" instead of the previously used "A" in the equations of comparison.)
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