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As far as I understand it, the Earth's magnetic field rotates around the planet's axis at the same rotational velocity as the planet's rotational velocity around its axis.

From what I understand about the interaction of a magnetic field and charged particles, the velocity of a moving magnetic field is a factor in how well a magnetic field will deflect/redirect charged particles that enter into it.

So, if the Earth's rotational velocity around its axis was faster, and say that this reduced the length of a day down to 22 hours, the Earth's magnetic field would then be moving faster and it should be more effective at deflecting/redirecting charged particles in the Sun's solar wind.

I am not a physicist or a scientist. I am asking this question simply out of scientific curiosity.

Would the Earth's magnetosphere be more effective against the Sun's solar wind if the planet's rotation was faster?

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  • $\begingroup$ I'm not sure I know what a moving magnetic field is. $\endgroup$
    – JEB
    Commented Jul 13, 2022 at 3:36
  • $\begingroup$ @JEB, I'm thinking about how the Earth's magnetic pole rotates around the planet's geographical pole during a 24 hour period. $\endgroup$
    – user57467
    Commented Jul 13, 2022 at 11:33
  • $\begingroup$ If the planet rotated faster but the internal core dynamics were the same (i.e., no enhanced dynamo), then the magnetosphere would be more volatile, not better. That is, there would be more substorms and geomagnetic storms due to the changing magnetic field orientation and strength (rotating, tilted dipoles are not symmetric with respect to the Sun direction). The current answer is only really correct in the last paragraph/statement... $\endgroup$ Commented Jul 14, 2022 at 15:17

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The Earth's magnetic field is rather stable, with some small variations due to atmospheric effects on short timescales and major changes (such as flipping of North and South pole) on very long timescales.

The majority of the magnetic field is produced by the Earth's core. This is called the geodynamo (https://en.m.wikipedia.org/wiki/Dynamo_theory). The outer core consist of melted, fluid metal, so a conductive material. This is moving in large convective streams (so we have motion of charges). As the Earth core rotates, the convective streams experience a Coriolis force (which are also the reason for the rotation of thunder storms in the atmosphere, for example). The result are rolls of circulating conductive currents, and these produce the magnetic field.

So this mechanism is based on the core's rotation and is rather stable. But if the core would rotate faster, the dynamo effect would be of course stronger and the magnetic field as well.

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