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#1 2012-02-20 22:07:42

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-21
Posts: 2,842
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Artificial Magnetosphere - Electromagnetic Induction

Are there any electrical engineers here who specialize in transformer design? We need to design the largest transformer ever built.

The purpose of this is to design a radiation shield for Mars. Earth has a magnetosphere, which is a magnetic field that traps ionized plasma from solar wind. Much of the plasma gets deflected, but some gets trapped. This charged plasma orbits the Earth. Any rotating charge creates a magnetic field. This expands Earth's magnetic field, extending it farther from the Earth. This traps more plasma, which expands the magnetic field further, etc. The maximum size of the magnetosphere is determined by the strength of magnet you start with. The magnetosphere will deflect both charged plasma from the Sun, and charged particle radiation. Deflecting charged particle radiation farther away is important because the farther away the less angle of deflection you need to miss the Earth. Some solar wind does get through, causing water in Earth's upper atmosphere to break up into hydroxyl (OH-) and positive hydrogen atoms. Some of these free hydrogen atoms are accelerated by impact with radiation to achieve escape velocity. Earth loses water this way; well, the hydrogen part of water. But the magnetosphere forms a tail behind the Earth, in the wake of solar wind. This tail re-captures most of the hydrogen we lose, drawing it back through the centre of the tail to the Earth. That re-captured hydrogen combined with captured solar wind enters the atmosphere where the magnetic field lines descend to the Earth, at the poles. When this re-captured hydrogen and captured plasma enters the atmosphere, it's called aurora. This works so well Earth gains more water than it loses.

This does two things: keeps water on the planet, and protects the planet from radiation. If we terraform Mars without a magnetosphere, it will lose its water to space. It would take over a hundred thousand years, possibly hundreds of thousands, but that's a short time in geological terms.

There is one proposal to build an electrical conductor around the equator of Mars. This electro-magnet would form an artificial magnetic field. But Earth's magnetic field is powered by its core. A Mars size planet hit the Earth 4.5 billion years ago; scientists are currently debating the 3rd digit in that date estimate, but 4.5 is close enough. That impact caused threw up a huge chunk of Earth's crust and mantle into space, as well as a large portion of that other planet's crust and mantle. The core of that other planet descended in Earth, adding to our planet. Some of the debris fell back to the Earth, but much went into orbit. The debris that went into orbit coalesced to become the Moon. The Moon was very close at first, but receded away. Earth's length of day immediately after the collision was 8 hours; it was a glancing blow. Tides from the Moon were much stronger when it was close, causing Earth's rotation to slow, each day became longer. But gravity from the Moon acts on the mantle and crust, not the inner core. As the Earth's rotation slowed, the inner core didn't. Only friction through the liquid outer core slowed the inner core. Today Earth's inner core continues to spin faster than the rest of our planet. This is what drives our strong magnetic field. The inner core is very hot, and some believe most of the uranium sunk to the core creating a giant nuclear reactor. Heat from the inner core transports through the liquid outer core to the mantle. Convection currents tend to counter rotate so that adjacent convection cells will have liquid either rising or descending together. Counter rotating cells will cancel any magnetic effects. However, with the inner core spinning faster than the mantle, the outer core will act as a liquid bearing. This will drive convection cells to rotate generally in the same direction. That coordination of convection cells creates the dynamo that generates Earth's magnetic field. To summarize: this dynamo is powered by heat from Earth's inner core, but coordinating those convection is what makes it a dynamo. So how do we do that on Mars?

Mars does not have a large moon, so its inner core will rotate the same rate as the rest of the planet. I propose we build a planet circling electro-magnet, but manipulate the magnetic field to act as the primary coil of a transformer. The goal is to manipulate convection cells in Mars' outer core to coordinate them. This way we can leverage energy from the planet's inner core to create a stronger magnetic field.

So, how do we design a magnetic field coil encircling the equator of Mars, but designed to induce an electric current in the outer core? Mars is 6,794.4km diameter at the equator, the outer core is believed to be about 3,000km diameter. That means the surface of the core is 1,897.2km down from the surface of the planet. How do we induce an electric current in high pressure molten iron that deep? That’s the first question. The second question is what do we have to do to the outer core to manipulate the convection cells to create a dynamo? That’s trickier, let’s start with the first question.

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#2 2012-02-21 00:37:50

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

The Earths protective field is electrostatic and not really magnetic lines of flux but held in place by them. Coersed if it the shape by how a magnet works. The flux decreases with distance just like gravity does from the Earths surface.

http://en.wikipedia.org/wiki/Van_Allen_radiation_belt

The inner electron Van Allen Belt extends typically from an altitude of 1.2 to 3 Earth radii (L values of 1 to 3). The inner belt contains high concentrations of electrons in the range of hundreds of keV and energetic protons with energies exceeding 100 MeV, trapped by the strong (relative to the outer belts) magnetic fields in the region.

The large outer radiation belt extends from an altitude of about three to ten Earth radii (RE) or 13,000 to 60,000 kilometres above the Earth's surface. Its greatest intensity is usually around 4–5 RE.

The outer belt consists mainly of high energy (0.1–10 MeV) electrons trapped by the Earth's magnetosphere.

http://en.wikipedia.org/wiki/Earth%27s_magnetic_field

Earth's magnetic field (also known as the geomagnetic field) is the magnetic field that extends from the Earth's inner core to where it meets the solar wind, a stream of energetic particles emanating from the Sun. The intensity of the field is greatest near the poles and weaker near the Equator. It is generally reported in nanoteslas (nT) or gauss, with 1 gauss = 100,000 nT. It ranges from about 25,000–65,000 nT, or 0.25–0.65 gauss

mearthbar.gif

Core dynamics are lower in this link...

This actually was talked of a bit on MarsDrive but for another reason
http://www.marsdrive.com/forums.aspx?g=posts&t=302

Also on another site with regards to radioactive decay for the core of Earth...

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#3 2012-02-21 03:00:10

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

Now a transformer works a bit differently in that the core needs AC to be fed into the primary coil with a secondary to be the output. The core induced flux is alternating as well such that the North and South pole are also moving from end to end of the transformer core.


Now to have a stationary pole would require DC being applied to a coil that is wrapped around a rod core. That would appear to look like what is happening with the Earths poles and magnetic field. Magnetic Field Produced by a Coil
coil1.gif

However once the core is charge to capacity of flux density ( saturation ) which is a function of the Permeability of the core material.

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#4 2012-02-21 03:01:48

RobertDyck
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From: Winnipeg, Canada
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Re: Artificial Magnetosphere - Electromagnetic Induction

And when the plasma of solar wind impacts the plasma of Van Allen Belts, the plasma-vs-plasma reaction deflects solar wind.
http://www.minimagnetosphere.rl.ac.uk/

works28.jpg pic3mag_rendition.jpg

Last edited by RobertDyck (2012-02-23 16:43:58)

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#5 2012-02-21 03:06:34

RobertDyck
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From: Winnipeg, Canada
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Re: Artificial Magnetosphere - Electromagnetic Induction

How do we induce a current in the liquid outer core? A current moving in a single direction (DC = Direct Current, for those who are reading this) wrapped around a solid inner core.

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#6 2012-02-21 11:58:34

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

Here is how a toriod core and coil field appears ....http://en.wikipedia.org/wiki/Toroidal_inductors_and_transformers

Magnetic_Vector_Potential_Circular_Toroid.jpg

Look simular does it not....

Is it important to create the flux field in the core?

Why not create the barrier in orbit by using lots of smaller field linked north to south to create the desired field flux line effect. The way the solar wind blows indicates that the stronger field needs to face the sun while a smaller in the shadow would be smaller. The orbiting satelite field generators then could be in a synchronous orbit facing the sun, whether they get the power from solar panels or from an RTG at first maked little difference just so that the coils fields all face the correct way.


To simulate a spinning core one would blank lines of flux that run from pole to pole alternately turning them on an off as if the planets core was the rotor and the field was pulsing it to make it move.

Last edited by SpaceNut (2012-02-21 11:59:55)

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#7 2012-02-21 23:19:27

RobertDyck
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From: Winnipeg, Canada
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Re: Artificial Magnetosphere - Electromagnetic Induction

The reason for doing it in the core, is to leverage the power from the core itself. Don't try to create a planetary magnetic field with brute force. Don't try to power it yourself. Instead manipulate currents in the outer core so energy from the core of the planet powers the magnetic field.

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#8 2012-02-21 23:43:10

Void
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Posts: 613

Re: Artificial Magnetosphere - Electromagnetic Induction

My best attempt to create an inducer would be to put orbital objects in the same orbit, spaced at even intervals, and then to create a hot cathode to boil off electrons towards the next orbital object.  Each orbital eliment would serve as a anode to the cathode of the other.  To create a circuit, they would all have to be in action.  The circuit would be an electron current passing between the collection of orbital objects.  The field produced should have a field pointed at the north and south Martian poles, presuming that this "Circuit" of orbital objects were to orbit at the equator.  If in the Martian interior there existed the convection of a fluid having magnetic properties, then perhaps some induced effect would occur, but I am quite out of my league in this, just grasping at straws, due to the nature of your request which is made with limited scientific information on what is the process inside of Mars.
That is not against you, but to say that I sort of have a notion, but notions at this level are usually wrong, but might be next door to something worth thinking about.

It is not required that the objects would orbit the equator.

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#9 2012-02-22 04:51:51

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

I guess that I did not understand the direction of thought that you were in RobertDyck but I will try.

We found out that mars had a liquid core around 2003 http://www.sciencedaily.com/releases/20 … 071457.htm
and with any discovery there is a but
http://news.nationalgeographic.com/news … -core.html
Mars's Liquid Center Cooling in Unusual Manner, Study Suggests sort of to a
http://www.space.com/3874-mars-gooey-core-freezing.html
Mars' Gooey Core is Freezing

The field generated in a coil drops real quickly as you move a way from the coil.
http://instruct.tri-c.edu/fgram/web/Mdipole.htm
That said getting the coils close to the core I think is beyound the capability to accomplish.

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#10 2012-02-22 12:09:06

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

Looking back at the Earth model we have been told that that Earth is a dynamo in the core that generates the mega-sphere.
When looking at how the power gets into the core one should look back to the natural nuclear reactors (RTG or Fission) which due to there nature is DC.
Unlike the Suns Fussion which I would class as AC.

So for the Earths core to rotate and to see currents one would then be led to Induction motor design....

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#11 2012-02-22 19:08:48

RobertDyck
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Re: Artificial Magnetosphere - Electromagnetic Induction

One mistake many scientists keep making is assuming that Mars lack of a magnetic field is caused by its core freezing. What I'm saying is once the rotation of Mars inner core synchronized with the rest of the planet, convection cells in the outer core changed to pure counter rotation. That resulted in a weak magnetic field from each convection cell, with each magnetic field pointing in a different direction, and tending to point in opposite directions. To create a planetary magnetic field we need to coordinate the convection cells.

Whether Mars inner core is solid like Earth or a slush ball of iron-nickel snow flakes mixied with metal sulphide liquid is interesting, but irrelevant. It still means Mars has a solid inner core and liquid outer core.

I'm aware that magnetic strength falls off dramatically with distance. I'm hoping it works like light. When lighting a room, a point source like a light bulb will fall off by the inverse square of distance: 1/d^2. So a light bulb on a very high ceiling will produce very little light on the floor. However, a line of fluorescent tubes across the entire length of the room acts as a line source. A line source falls off linearly, as the inverse of distance: 1/d. A set of fluorescent light tubes behind a diffuser panels, with the panels either filling the entire ceiling or tiled a cross the ceiling at regular intervals act differently. They act as a plane source. Light from a plane covering the entire ceiling does not fall off by distance at all. So this means light from the ceiling is the same as light at the floor, regardless of ceiling height. You'll notice all public buildings with very tall ceilings use this method of illumination, it's very efficient.

A planet circling electric conductor is a circle surrounding the core. I'm hoping that would add something. Or would it only act as a line source? A set of cables, equally space in latitude, over 60 degrees latitude of the core (not the surface, the core) would have to be 1299km north and south of the equator. If the core is 3000km diameter, it's 1500km radius. Sin 60° * 1500km = 1299km. That's straight north of a line from the core to the equator, it would extend to 22.48° latitude north and south. Mars has an axial tilt of 25.19° so that's almost to the tropics. Would this do it? Would multiple planet circling conductors within 22.48° latitude create a magnetic field that extends to the core without attenuation due to distance? It would still have 1900km of rock to go through.

Would such a set of conductors require a pulse, coordinated on all conductors, to create a magnetic field that would push electrons in the outer core?

Last edited by RobertDyck (2012-02-22 19:10:33)

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#12 2012-02-23 12:02:00

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

Light from a Flourescent tube, or LED comes out of its surface with a arc or radii or ilumination to it for why it spreads out. The diffuser panel that are used are flat on one side facing the light spource but with rows or pyrimidal shapes on the other, it works to change the beams straight line of direction by changing the surface that it exits out of by reflection and refraction methods.

Lines of magnetic flux do not work that way. They first align themselves via domains North to south such that a flield line of flux is created. This line of flux takes the path of least resistance to travel through matter based on a permeability index call it a efficiency of transfer number. The flux lines will follow the shape of the material.

The line of flux created from passing DC current through a conductor is not parrellel to the conductor but is at a right angle to it the current flow in the conductor.
seen at the link  http://en.wikipedia.org/wiki/File:Manoderecha.svg  from this page  http://en.wikipedia.org/wiki/Magnetic_field
The field is spread out through out the length of the conductor but it is very weak. To increase the flield lines of flux in a motor more conductors in parrallel are layed next to the first so on and so forth until the field strength reaches what is needed. The conductor if made as a loop circling the planet would have a huge resistance which would cause loss to the power coming into the conduct so an even weaker field would be created.

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#13 2012-02-23 17:31:18

RobertDyck
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From: Winnipeg, Canada
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Posts: 2,842
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Re: Artificial Magnetosphere - Electromagnetic Induction

The reason a plane of light acts without attenuation over distance is not due to focus, it's due to the plane. Light from each point along the plane acts together. The way they add up results in no loss with distance. Similar with a line, each point acts as a point source, but added together the total illumination attenuates linearly.

I expect a plane of magnets would act similarly. But a flat broad ring should actually focus its force within the ring. Circumference of the inner ring is smaller, so flat broad rings with equal width would have surface area proportional to circumference. That should focus the magnetic field proportional to the smaller circumference. Of course iron in the intervening rock would interfere with that.

Gravity Probe B included some very interesting technology. One was a lead bag chilled to near absolute zero. They found superconductor lead actually shields magnetic fields, it blocks Earth's magnetic field. It's the only known material that can shield a magnetic field. Lead becomes a superconductor at 7.193°K (according to the website Hyperphysics), but NASA chilled the lead bag on Gravity Probe B to 1.7°K. Helium boils at 4.2°K at 1 atmosphere pressure (according to Air Liquide, a company that makes liquefied gasses). So why did NASA chill lead that much colder? Is that temperature required to shield a magnetic field?
http://science.nasa.gov/science-news/sc … r_gpbtech/

Carbon nanofibres have less electrical resistance than copper, which has less than aluminum. Furthermore a cable of carbon nanofibres can carry 1,000 times as much current as aluminum for a cable the same diameter. For this reason I've argued for carbon nanofibre cables for long distance power transmission. If electrical loss was a significant factor, we could use superconductors. The problem is they require cryogenic temperatures, and coolant pumps required to keep them that cold consume power. Even with a Dewar to minimize heat loss, a superconductors still requires active cooling. My assertion is power to run those pumps is greater than power loss due to carbon nanofibre cables. That's for long distance power transmission, even over distance greater than 2,000km. Yes, power transmission lines that far here on Earth become practical if you use carbon nanofibre. Are you claiming a planet circling electromagnet on Mars would require a superconductor? Would superconductor lead shielding reflect the magnetic field down?

Last edited by RobertDyck (2012-02-23 17:32:04)

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#14 2012-02-24 03:24:37

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

The suggestion of helium cooled would not be practical as the amount of energy to get the temperatures would not be avialable.
The Carbon nanofiber sounds interesting but it does not seem to create a field when near a ferrite material which is important part of a magnetic field. http://en.wikipedia.org/wiki/Ferrite_(magnet)

http://en.wikipedia.org/wiki/Magnetite

The formula for magnetite may also be written as FeO·Fe2O3, which is one part wüstite (FeO) and one part hematite (Fe2O3). This refers to the different oxidation states of the iron in one structure, not a solid solution. The Curie temperature of magnetite is 858 K (585 °C; 1,085 °F).

http://webmineral.com/data/Magnetite.shtml

The motor analogy for what we see from the Earths outer mantle (stator) and the solid core(amature) speed difference is called Slip and is the lag from the pulsing of current that pushes or pulls the amature with respect to the Stator. The liquid core is like a ferrofluid material and gap between the Stator to the armature.

So why a hot liquid core?
The rate of change of temperature with depth is referred to as the geothermal gradient. The geothermal gradient varies depending on location, so there is no uniform answer. On average, the geothermal gradient is approximately 75 degrees F per mile. In volcanically active areas, the gradient can be as high as 150 degrees F per mile. In ocean trenches, the gradient may be as low as 15 degrees F per mile. Decay of naturally occurring radioactive elements may also cause localized increases in temperature in some locations. The temperature does rise with the density. The mantle is more dense than the crust and has a higher temperature, the core is more dense than the mantle and in turn it is also at a higher temperature.

The point was that once a Curie temperature has been achieved that the domains can be aligned throughout the material if a field is placed near to this molten hot material. Once the material is allowed to cool it will retain the direction that is setup. This is the principle used in the modern CD/DVD media.

So does that mean that the solid core is actually cooler than the molten liquid portion?

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#15 2012-03-03 11:10:33

karov
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From: Bulgaria
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Posts: 819

Re: Artificial Magnetosphere - Electromagnetic Induction

In fact the cables could be "plasma cords".

Alexander Bolonkin ( the , so to say, Russian Paul Birch ):

1. http://www.scribd.com/doc/63456356/List … on-8-28-11

2. http://www.scribd.com/doc/42721638/Wire … -Continent

3. http://www.archive.org/details/Wireless … oContinent

A plasma cord grid could deploy real high-definition 4D "plasma window" around any body. ( http://en.wikipedia.org/wiki/Plasma_window ). Add smart nano-dusticles embedded and participating in the plasma and you get the ultimate version of http://en.wikipedia.org/wiki/Mini-magne … propulsion , but used for environmental conditioning.

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#16 2012-03-10 03:44:44

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

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#17 2012-04-02 02:05:21

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

I must apologize for the tremendous delay in posting my response to all.....

Further up the response Void talked about inducing current flow and that is what induction motors do to the armeture which is a laminated layers of materials that when the frequency of the applied AC is present causes the motor to spin. With that is load on the shaft of the rotor as indicated by work being done as torque applied to what we need to move. When there is a difference of rotational speed of the stator and the armatures movement this is call slip.

The Earths core does spin at a different rate when compared to the crust which appears to spin more slowly. It would appear that the liquid area does decouple the rotation from the core to the crust such that there is apparant slip.

Gravity as defined as surface gravity on a planet can be determined from Newton 's Law of Universal Gravitation:
F = G m1m2 / R2 
Earths value
g = 9.81 m/s2 = 32.2 ft/s2

But since the earth is not coupled then there is centrifugal and centripical forces also to be put into any calculation.
http://www.answers.com/topic/centripetal-force
http://en.wikipedia.org/wiki/Centrifugal_force

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#18 2012-04-02 03:27:46

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

http://en.wikipedia.org/wiki/Magnetic_core
The shape of the core influences how the field lines form to the shape

http://www.intemag.com/calculators.html
How to figure out what forces are present with materials

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#19 2012-05-01 12:33:59

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

Found some other forums with the topic
http://www.physforum.com/index.php?showtopic=22193
http://sagansbrain.blogspot.com/2010/07 … icial.html
http://www.orionsarm.com/eg-article/4851d85e0791b
http://www.minimagnetosphere.rl.ac.uk/
http://www.thelivingmoon.com/45jack_fil … hield.html
http://www-ssc.igpp.ucla.edu/personnel/ … /mars_mag/
http://www.redcolony.com/art.php?id=0301280

The threads from the past may be lost here on putting nuclear material that is spent in the core and also of using nuke rich ore or to create a thermal melt down of that material to restart the core as well...

http://www.conservapedia.com/Mars

Magnetosphere
Mars has a very weak magnetic field. Data from various missions has established an upper limit of 2.1 * 1018 N-m/T on the magnetic dipole moment of Mars. According to Russell Humphreys's model of the creation of magnetic fields, Mars probably had a magnetic dipole moment at creation of 1.51 * 1023 N-m/T. Thus Mars's magnetic field has been decaying very rapidly. This tremendous decay, and the presence on Mercury of a magnetic field of significant strength, baffles astronomers who have assumed that magnetic fields form on rapidly moving planets that have conductive and liquid cores that can act as dynamos. In fact, Humphreys asserts that the characteristic that determines which of the terrestrial planets will have a persistent magnetic field is the core radius, and that the cores of all four of these planets have similar conductivities. Mercury and Earth have larger cores than do Mars and Venus. The lengths of the sidereal days on those worlds do not matter.[3]

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#20 2012-05-01 15:26:34

louis
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Re: Artificial Magnetosphere - Electromagnetic Induction

Couldn't we have satellites in orbit around Mars with connecting cables. These satellites would be solar power stations, fed by reflectors further out.  The cables would then create an electro-magnetic field. Is this feasible? It might not need to cover the whole of Mars - just the main area of settlement, perhaps a 1000 miles by 500 miles shall we say. What do you think?


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#21 2012-05-01 16:39:31

RobertDyck
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From: Winnipeg, Canada
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Re: Artificial Magnetosphere - Electromagnetic Induction

SpaceNut wrote:

Mars's magnetic field has been decaying very rapidly. This tremendous decay, and the presence on Mercury of a magnetic field of significant strength, baffles astronomers who have assumed that magnetic fields form on rapidly moving planets that have conductive and liquid cores that can act as dynamos.

I have been talking about a theory from the book Rare Earth: Why Complex Life Is Uncommon in the Universe. This book asserts that convection in any liquid, including the outer core of a planet, will form counter rotating cells. That's because fluid in two adjacent cells will rise together, and on the other side of the cell will fall together. Fluid in contact doesn't like flowing in opposite directions. Counter rotating cells will cancel each other's dynamo. To create a planet-wide dynamo it requires something to coordinate convection cells, so they rotate together. The author of this book argues that gravity from another body provides that coordinating force. For Earth, our Moon has gravity that creates tides. Those tides don't just act on oceans, but the crust itself. This creates a bulge in the Earth, and that bulge forms slowly subsides slowly, so as the Earth rotates with each day the bulge is slightly ahead of the Moon. The Moon's gravity pulls on that bulge causing Earth's rotation to slow down. This has been measured and confirmed, it is happening. This force slows the crust, not the inner core. The mantle is directly attached to the crust, but the liquid outer core separates the inner core from the rest of the planet. That means the inner core is still rotating faster than the rest of Earth. That difference in rotation between the inner core and mantle is what is organizing convection cells in the outer core. The liquid outer core is acting as a fluid bearing. Or to put it another way, the convection cells are acting like giant ball bearings.

Mercury is so close to the Sun that gravity from the Sun itself does the same thing. This explains why Earth and Mercury have strong magnetic fields. The lack of any large Moon explains why Venus and Mars do not. It also means Mars would have had a strong magnetic field when the planet first formed, causing differential rotation by some massive object hitting it during the planet's accretion. But without a large moon causing continuous change in rotation of the crust, its inner core quickly synchronized with the rest of the planet. Once synchronization occurred, the planet's dynamo stopped.

I am constantly amazed by the number of people who blatantly ignore this.

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#22 2012-05-01 21:56:40

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

That would make the moons cause bulge of the earths crust the drag on the armature which is the applied torque of the motor concepts.

The moon lies, on average, 384,400 km (238,900 miles) away and takes 27.3 days to orbit the Earth.
tide_moon.jpg

As the moon orbits the Earth, the tidal bulges move with it, making one revolution every 24 hours and 50 minutes.

tide_moonsun.jpg

Lunar Surface gravity at the equator is 5.32 ft/sec2 (1.622 m/sec2), compared to 32.174 ft/sec2 (9.806 m/sec2) of Earth. That's 16.5% or nearly exactly 1/6 Earth's gravity.

  • Body Multiple of Earth gravity m/s2
    Sun         27.90               274.1
    Mercury   0.3770               3.703
    Venus      0.9032              8.872

    Earth       1                    9.8067[11]
    Moon      0.1655              1.625

    Mars       0.3895             3.728

    Jupiter      2.640            25.93
    Io            0.182             1.789
    Europa      0.134            1.314
    Ganymede 0.145            1.426
    Callisto      0.126           1.24

    Saturn       1.139            11.19
    Titan         0.138            1.3455

    Uranus       0.917            9.01
    Titania       0.039            0.379
    Oberon       0.035            0.347

    Neptune     1.148           11.28
    Triton          0.079          0.779

    Pluto            0.0621       0.610
    Eris         0.0814 (approx.) 0.8 (approx.)

Last edited by SpaceNut (2012-05-01 22:07:12)

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#23 2012-05-01 22:39:05

Void
Member
Registered: 2011-12-29
Posts: 613

Re: Artificial Magnetosphere - Electromagnetic Induction

RobertDyck Said:

Once synchronization occurred, the planet's dynamo stopped.

Well then if the major sheild volcanos of Mars were a Mascon, and a massive object were placed in geosynch, then a gravitational coupling which would resist some degree of force beyond the Martian velocity of rotation?

With the hopes for Asteroid Mining, and presumed advancements in human abilities, then an object placed there, and it having arrays to harvest energy from the momentum of the solar wind?  Then a drag to slow down the crust of Mars?

That is the average force of the solar wind would be null more or less as the object orbited Mars, but the orbital speed of the object itself would drag against plasma magnetic lines of force, and if the degree of drag did not exceed the gravitational coupling of the shield volcano mascon and the orbital object, then this would slow down the crust, and also generate a lot of electrical power.

The object would be much closer to the crust of Mars than is our Moon, but it is presumed that it would be very much smaller.

So, how much of a magnetic field is enough?  1% of Earth?, 5%?, 10%?

I am not saying that it would be enough, but based on what you have said, a people who could set this up would achieve a magnetic field of some sort.

Last edited by Void (2012-05-02 01:36:53)

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#24 2012-05-07 00:11:47

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 1,108
Website

Re: Artificial Magnetosphere - Electromagnetic Induction

Might it not be easier to just replenish atmospheric gases every few centuries-to-millennia with asteroid/comet impacts,  than to attempt planetary engineering on the scale of adding a massive moon?  Or building a planet-girdling conductor and energizing it?  Just the odd thought from an old guy.

GW


GW Johnson
McGregor,  Texas

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#25 2012-05-07 04:01:33

SpaceNut
Moderator
From: New Hampshire
Registered: 2004-07-22
Posts: 6,265

Re: Artificial Magnetosphere - Electromagnetic Induction

Lets make the leap of faith that the moons tug causes the magnetic field... Then the fact that the moon approaches the earth about 50,000 km closer than the other ("apogee") will make the Full Moons 14% bigger and 30% brighter than other full Moons of 2012 due to the oval shape of the Moon's orbit.
Lunar Perigee and Apogee Calculator


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A perigee Moon brings with it extra-high "perigean tides," but this is nothing to worry about, according to NOAA. In most places, lunar gravity at perigee pulls tide waters only a few centimeters (an inch or so) higher than usual. Local geography can amplify the effect to about 15 centimeters (six inches)--not exactly a great flood.

The rotation of the Earth creates the equatorial bulge so that the equatorial diameter is 43 km larger than the pole to pole diameter.

The internal heat of the planet is probably produced by the radioactive decay of potassium-40, uranium-238 and thorium-232 isotopes. All three have half-life decay periods of more than a billion years. At the centre of the planet, the temperature may be up to 7,000 K and the pressure could reach 360  GPa. A portion of the core's thermal energy is transported toward the crust by Mantle plumes; a form of convection consisting of upwellings of higher-temperature rock. These plumes can produce hotspots and flood basalts.

The Hill sphere (gravitational sphere of influence) of the Earth is about 1.5 Gm (or 1,500,000 kilometers) in radius. This is maximum distance at which the Earth's gravitational influence is stronger than the more distant Sun and planets. Objects must orbit the Earth within this radius, or they can become unbound by the gravitational perturbation of the Sun.

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Mercury, Venus, Earth, and Mars

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