Possible to extract energy from magnetosphere?


by GreenAce92
Tags: energy, extract, magnetosphere
GreenAce92
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#1
Jun27-13, 11:35 PM
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I just had this idea/vision of panels being placed in front of the sun, then the energy collected is beamed to a receiver/transmitter orbiting Earth. I suppose with an energy 'Magnitude' of the sun, a little bit of 'loss' due to Earth's atmosphere is not a big deal but... I wondered what if you could 'saturate' the Earth's magnetosphere and then draw energy from that... instead of building a receiver on the ground of Earth. The receivers on the ground could then just point at the sky to receive power.

Anyway, assuming that all of my ideas are probably wrong, like a misunderstanding... if such an idea was possible, would Earth's laws not allow someone to mess with the Magnetosphere?

I just thought with radio propagation and all through space without inhibitance (haha made up words), then it isn't really necessary to transport panels close to the sun.
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davenn
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Jun27-13, 11:49 PM
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there's more energy "falling" directly into the magnetosphere from the sun than what you could ever collect on earth and transmit back up to it

all in all... a totally waste of time, sorry

cheers
Dave
GreenAce92
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#3
Jun28-13, 12:06 AM
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No need to be sorry, it was just an open question without backing.

I read this 'fact' from a book I found in the basement of the physics department of a University I used to attend.

For every square mile of direct sunlight exposure, there is five million horsepower.

Does that seem right? And if so, is it just about money then why this isn't being followed?

davenn
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Jun28-13, 12:21 AM
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Possible to extract energy from magnetosphere?


dunno if that's a correct figure, would have to work it out
but a figure more useable is ~ 1kW / metre2 ... from memory, that's an approx. avg. as there is more under direct overhead sun at equatorial regions compared to high latitude

then depending on how you intended sending it back to the magnetosphere and the losses involved there, an RF ( radio) signal is VERY lossy.

you would in the long run still be better off somehow directly generating energy from within the magnetosphere and beaming to earth and getting rid of 3 major inefficiencies ( big losses) of your original system

NASA have experimented with towing a tether from a space shuttle a few years back for electricity generation. cant remember the final results ... I think the tether broke ?? do some googling

Dave
DrZoidberg
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#5
Jun28-13, 08:40 PM
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An electrodynamic tether is essentially a homopolar generator/motor http://en.wikipedia.org/wiki/Electrodynamic_tether
It can convert kinetic/potential energy of a spacecraft into electricity and the other way around. But it doesn't extract energy from the magnetosphere.
davenn
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Jun28-13, 08:55 PM
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Quote Quote by DrZoidberg View Post
An electrodynamic tether is essentially a homopolar generator/motor http://en.wikipedia.org/wiki/Electrodynamic_tether
It can convert kinetic/potential energy of a spacecraft into electricity and the other way around. But it doesn't extract energy from the magnetosphere.
not really....

you obviously didnt read all the link you gave
from wiki

Main article: Electrical generator

A space object, i.e. a satellite in Earth orbit, or any other space object either natural or man made, is physically connected to the tether system. The tether system comprises a deployer from which a conductive tether having a bare segment extends upward from space object. The positively biased anode end of tether collects electrons from the ionosphere as space object moves in direction across the Earth's magnetic field. These electrons flow through the conductive structure of the tether to the power system interface, where it supplies power to an associated load, not shown. The electrons then flow to the negatively biased cathode where electrons are ejected into the space plasma, thus completing the electric circuit. (source: U.S. Patent 6,116,544, "Electrodynamic Tether And Method of Use".)An electrodynamic tether is attached to an object, the tether being oriented at an angle to the local vertical between the object and a planet with a magnetic field. When the tether cuts the planet's magnetic field, it generates a current, and thereby converts some of the orbiting body's kinetic energy to electrical energy. As a result of this process, an electrodynamic force acts on the tether and attached object, slowing their orbital motion. The tether's far end can be left bare, making electrical contact with the ionosphere. Functionally, electrons flow from the space plasma into the conductive tether, are passed through a resistive load in a control unit and are emitted into the space plasma by an electron emitter as free electrons. In principle, compact high-current tether power generators are possible and, with basic hardware, tens, hundreds, and thousands of kilowatts appears to be attainable


its still more to do with good old fashion cutting through a magnetic field with a moving wire power. generation
The movement of the wire is just being accomplished by a different method. The magnetic field is still needed

Dave
DrZoidberg
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#7
Jun28-13, 09:50 PM
P: 371
This does not contradict my statements. A wire continuously cutting through a magnetic field to produce a direct current is a form of homopolar generator. And even though the magnetic field is important for this to work the energy does not come from the field but from the motion of the wire.
Viracocha
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#8
Jun28-13, 11:14 PM
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might be possible, but it probable wouldn't be very efficient, you'd have too many things contributing to energy loss (I'd have to think a main one would be the panels moving/vibrating from the energy instead of storing it electrically). By the time it would be plausible we'd have much more efficient means of energy production anyway...
mhumm2
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#9
Jun29-13, 02:06 AM
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Intriguing conversation. I didn't know wp had an entry like that. I've actually thought about a version of this. Suppose a wire-wound inductor the size of a Grey-hound bus could be built and put into an orbit just a bit higher in altitude than a standard geosyncronous orbit so that it's path around the Earth was at a 90 degree angle to the magnetic field. Suppose that satelite or "rotor" was tethered to the Earth with a pair of conductors built in. As the rotor "cuts" the lines of flux, there would be gobs of current (yes, i typed "gobs"). Wouldn't this basically be a (macro) motor? And i believe it would be DC, yes? Of course the obvious challenge is the tether. The stress would be significant and not necessarily static. But imagine if something like that could be built.


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