|MadSci Network: Earth Sciences|
John, The short answer to your question is no. The earth's magnetic field is believed to be due to complex convection patterns in the outer core. These are driven by the heat of radioactive decay, accretion energy from the formation of the earth and the energy given off as the material at the base of the outer core freezes to the inner core. The energy driving the convection will eventually dissipate and the earth's field will go away. This will take several billion years. Do a web search on “geodynamo”. The earth's magnetic field is complicated and changing. The simplest description is that of a dipole (or bar magnet) that is off center and tilted relative to the spin axis of the earth. Like many simple descriptions, there are a lot of details that get overlooked. For one, the magnetic poles are moving. For another, the strength of the field has dropped by roughly one half since Roman times. Since reliable direct measurements were first made around 1845, the strength has dropped by 10%. This has prompted speculation that the magnetic field may be starting a reversal. The magnetic field offers some protection from charged particles from the sun. Having the magnetic field go away is probably not desirable. The details of a reversal are not sufficiently well known to say if the field strength would go to zero at some point. The geodynamo models generally indicate this won't happen. It appears that the poles will split into several poles and migrate to the opposite hemisphere over several thousand years. However, in the absence of detailed knowledge of what happens during a reversal, a proposal was made that could approximate what you are suggesting. The object of the proposal was to use current carrying coils going completely around the world at several latitudes to maintain something like the current dipole field. This would literally be the largest structures ever made. Reversing the current flow would reduce the field instead of maintaining it. David
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