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#1 2014-02-17 03:48:59

m arvin
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Registered: 2014-02-14
Posts: 3

Mars has locally strong magnetosphere

I have seen many posts on this forum about Mars having no magnetosphere. Mars has one, albeit it is very different from that on Earth.

http://mepag.nasa.gov/topten.cfm?topten=5

"Mars Global Surveyor discovered and mapped intense magnetization in the Martian crust."

http://science1.nasa.gov/science-news/s … st31jan_1/

"Locally, the magnetic fields arch over the surface like umbrellas, hundreds of km high. "If you were standing on Mars in one of these areas," says Mitchell, "you would measure a magnetic field about as strong as Earth's -- a few tenths of a gauss."

"Places where magnetic umbrellas deflect the solar wind are also spots where the ionosphere is retained high above the surface of the planet."

Is the latter quote implying, that a vertical pillar of the atmosphere would be heavier in total at some regions? Ionosphere has low density, would not the difference be negligible?

EDIT: I have found a thread on these forums, that has already discussed some aspects of the topic of crustal magnetosphere: http://www.newmars.com/forums/viewtopic.php?id=6824.

Last edited by m arvin (2014-02-17 04:46:07)

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#2 2014-02-17 13:32:02

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,623
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Re: Mars has locally strong magnetosphere

It's my understanding from what I have seen and read,  that these localized magnetic fields are remnant fields frozen into isolated structures in the crust,  left over from a time long ago when Mars had a strong global field.  I'm guessing there is no longer any fluid overturn to power the iron core dynamo.  May also explain the lack of tectonic plate activity.  It all froze solid long ago.

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#3 2014-02-17 14:10:49

Quaoar
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Registered: 2013-12-13
Posts: 600

Re: Mars has locally strong magnetosphere

GW Johnson wrote:

It's my understanding from what I have seen and read,  that these localized magnetic fields are remnant fields frozen into isolated structures in the crust,  left over from a time long ago when Mars had a strong global field.  I'm guessing there is no longer any fluid overturn to power the iron core dynamo.  May also explain the lack of tectonic plate activity.  It all froze solid long ago.

GW

Yes, probably this place are contains iron rich rocks that remain magnetized even if the global field vanished. This local magnetic field may offer protection against cosmic ray. So another possible criteria for landing site choiche may be the presence of a strong local magnetic field.

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#4 2014-02-17 14:24:13

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,774
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Re: Mars has locally strong magnetosphere

These magnetic fields tend to be a high altitude locations. Old crust. We found a location that satisfies other criteria: flat/smooth, near equator, low altitude, water. That was hard enough, and the water is in doubt. Yet another criteria could eliminate any solution.

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#5 2014-02-18 04:24:07

m arvin
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Registered: 2014-02-14
Posts: 3

Re: Mars has locally strong magnetosphere

RobertDyck wrote:

These magnetic fields tend to be a high altitude locations. We found a location that satisfies other criteria: flat/smooth, near equator, low altitude, water. That was hard enough, and the water is in doubt. Yet another criteria could eliminate any solution.

Generally, yes. Although there are exceptions, like ~ 165E 15S, where the magnetic field is strong, the altitude is around -3km, and flat crater basins exist. It is not at the equator, though, what might be a problem. Summers are even hotter there than on the equator, ~25 Celsius vs 5, but winters colder, -35 vs -15. No idea about water there, but sighted atmospheric phenomena have been observed nearby.

Last edited by m arvin (2014-02-18 06:30:16)

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#6 2014-02-19 16:00:02

Quaoar
Member
Registered: 2013-12-13
Posts: 600

Re: Mars has locally strong magnetosphere

It is possible to protect the settlement with an artificial mini-magnetosphere, powered by the ERV 100 KW nuclear reactor, when fuel production is finished:

http://earthweb.ess.washington.edu/spac … elding.pdf

If there are iron rich metallic rocks near the base, they will become magnetized enhancing the cosmic ray shielding effect.

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#7 2014-02-19 16:13:14

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
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Re: Mars has locally strong magnetosphere

Mini-magnetosphere is a very thin plasma held in a strong magnetic field. Atmosphere has much greater gas density, even Mars. Wind would blow away the plasma, static discharge would neutralize it's charge, and gas conduction/convection would cool plasma to gas. So no, mini-magnetosphere cannot operate in an atmosphere. You would be restricted to a magnetic field alone.

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#8 2014-02-20 01:34:46

Quaoar
Member
Registered: 2013-12-13
Posts: 600

Re: Mars has locally strong magnetosphere

RobertDyck wrote:

Mini-magnetosphere is a very thin plasma held in a strong magnetic field. Atmosphere has much greater gas density, even Mars. Wind would blow away the plasma, static discharge would neutralize it's charge, and gas conduction/convection would cool plasma to gas. So no, mini-magnetosphere cannot operate in an atmosphere. You would be restricted to a magnetic field alone.

So we can use it on the Moon, but not on Mars. What's about protecting the base with an interred large coil, made with a superconductive wire?

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