Artificial Magnetic Poles for Mars?

I would have thought the concern should be more on the lack of a planetary defence screen from cosmic radiation from the sun... On earth we have the Van Allen belt created by the Earth's magnetism, on Mars there would be little protection.

As for the lack of a magnetic field being the prime reason for a lack of atmosphere, I believe the main reason is the smaller size of the planet compared to Earth and the reduced escape velocity for the gases to overcome...

John.

Hi John, I've heard the argument about the lower escape velocity before, but I've always thought there has to be bigger factor. My reasoning is Venus!

If you're looking more or less to duplicate Earth's magnetic field (you didn't say), you're looking at currents in the billions of amps. Perhaps several hundred billion amps in, say, a ring about the planet's equator.

-e

I realize that my previous response doesn't answer the question of "how much energy...," but computing the total energy in such a field is complicated not only by the effects of the solar wind on the shape and extent of the field, but also by contributions from the magnetosphere that forms as a result. If the field in question were simply of a laboratory-scale current ring or solenoid, the problem reduces to one of computing the total energy in a symmetric dipole field. But you're asking about an altogether different beast.

Calculating the energy needed to sustain a planetary-scale field embedded in a supersonic, highly-ionized plasma (itself containing an entrained magnetic field which flip-flops on a regular basis) is an extremely complicated problem - hence the ambiguity in my electric-current estimates for an equatorial ring and no answer at all for total energy.

-e

Thanks, E.

The problem is apparently beyond our capability to handle with present technology, but who knows what may happen in the future.I would think that to fully utilize Mars, the magnetic field would have to be restored as protection for all life forms from radiation and solar wind.Perhaps a nuclear or matter-antimatter reactor at the core of the planet would do it.Pure speculation, I know, but imagination is a free ride.

"Perhaps a nuclear or matter-antimatter reactor at the core of the planet would do it.Pure speculation, I know, but imagination is a free ride."

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A reactor (nuke, fusion, anitmatter) I would build on the surface, not at the core. Systems this complex need a lot of hand-holding - particularly where servicing is concerned. A well-shielded reactor (even a m/a reactor, whose reaction products are gamma rays) should not require deep burial any more than current reactors, and would certainly be easier to maintain.

Another thought. By using superconductors, once you've established full current (which could be done gradually), your energy budget would drop to that of maintaining the field. Yes, superconductors have no resistance, but the field itself is buffeted constantly by the solar wind and occasional solar flare or CME. This does work on the field and could affect the net current in the ring (or whatever appropriate topology is used). You need lots of strands of superconductor for each winding. Too high a current density per conductor or too high a flux density and you quench the superconduction. With all that current suddenly going through a resistance, you can bet the whole thing would put on a planet-girdling show (not to mention the effect your collapsing faux magnetosphere might have on Mars' upper atmosphere!)

-e