Mini-Magnetospheres on Mars?

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The Technical University of Denmark has a page about the Martian magnetosphere in which it mentions the existence of localized mini-magnetospheres on Mars that are more powerful than the global field around Earth (source). What causes the mini-magnetospheres and how extensive is their strength and coverage of Mars?
 

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davenn
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The Technical University of Denmark has a page about the Martian magnetosphere in which it mentions the existence of localized mini-magnetospheres on Mars that are more powerful than the global field around Earth (source).
It doesn't say that it says .... These measurements showed the existence of powerful magnetic crustal fields on the planet’s surface, far more powerful than those found on Earth.

operative words being "crustal fields on the planet’s surface and on Earth"

Its referring to Crustal fields on the surface .... NOT the global field


What causes the mini-magnetospheres and how extensive is their strength and coverage of Mars?
possibly cause by magnetised iron deposits ... the map in the article shows how extensive they are



Dave
 
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davenn
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What causes the mini-magnetospheres
OK here's an article that goes to confirm my previous comment about iron deposits

https://phys.org/news/2014-02-magnetic-crustal-fields-affect-planets.html

They don't work because there is not one magnetic field on Mars, rather there are dozens. These small fields are powerful, concentrated in the crust, and scattered over the surface of the planet. In their absence, compass needles would lie still; in their presence, they spin, pointing first at one bar magnet, then another. How well these crustal fields protect the planet is a mystery, and one that may be solved soon by the MAVEN satellite, which is on its way to Mars right now.

What we do know is that if a compass ever worked well on Mars, it was over 3.5 billion years ago. Before that time, Mars had a molten core, whose contents constantly churned upward towards the surface. This process of convection permitted cooling of the interior, as well as active volcanism in the highlands and plains. Volcanoes brought iron to the surface, giving Mars its signature color. Iron in the core also moved electrons, which created a planetary dynamo: a device that converts mechanical energy into electric energy. Electric fields generate magnetic fields. Large magnetic fields can provide protection from solar wind for any planet as long its interior maintains a steadfast supply of molten metal.

Large magnetic fields also decay unless maintained. After the first billion years or so, the Martian interior cooled to the point where convection halted. When the iron ceased to flow, the dynamo died. Volcanism declined. The last iron deposits from the interior left their marks as pockets of magnetism, called crustal anomalies, largely sequestered in the southern hemisphere.

Dave
 
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