Solar power without solar cells

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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Giorgio
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Solar power without solar cells

Post by Giorgio »

Via Physorg:
http://www.physorg.com/news/2011-04-sol ... netic.html
Light has electric and magnetic components. Until now, scientists thought the effects of the magnetic field were so weak that they could be ignored. What Rand and his colleagues found is that at the right intensity, when light is traveling through a material that does not conduct electricity, the light field can generate magnetic effects that are 100 million times stronger than previously expected. Under these circumstances, the magnetic effects develop strength equivalent to a strong electric effect.


Abstract from Journal of Applied Physics:
http://ieeexplore.ieee.org/search/frees ... er=5738604
Abstract

Charge separation mediated by linearly-polarized light in transparent insulators is analyzed numerically by integrating the equations of motion of a bound charge. It is shown that large static and transient dipole moments can be induced by the magnetic component of light at nonrelativistic intensities regardless of whether the pumplight is coherent or incoherent. Quantitative estimates show that efficient conversion of optical beams to electrical power is possible in lossless dielectric media and that THz radiation can be generated in unbiased materials through the use of transverse optical magnetism.

ladajo
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Post by ladajo »

Now this is REALLY interesting.

Nice find Giorgio.

D Tibbets
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Post by D Tibbets »

"..at the right intensity.."

That is a rather ambiguous statement. It could be interpreted to mean that at 1,000,000 times the light intensity, the magnetic effects will be 1,000,000 times stronger. Totally useless, from an efficiency standpoint.

If they said that past some threshold of light intensity, the magnetic effects are changed. That would be possibly useful. Or if it had some modifying effect on the electrical side that changed overall efficiency (and the material was not quickly vaporized)...

And what does "non relativistic intensity" mean when the topic is light . Intensity implies power, not speed. And the speed of light is constant in a material. There may be meat in the artical, but these tidbits seem confusing at best.

Dan Tibbets
Last edited by D Tibbets on Thu Apr 14, 2011 4:11 pm, edited 1 time in total.
To error is human... and I'm very human.

Giorgio
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Post by Giorgio »

I guess that to understand what they mean we will have to wait until we can read the article.
I searched about it on the web but at no avail.

Let's see in the coming weeks.

Nik
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My take...

Post by Nik »

After reading the PhysOrg article, I got the impression that this discovery is like 'giant magneto-resistance' a few years ago: When we knew it was possible, it needed optimised materials to be commercially viable...

And now they're the read-heads in a zillion hard-drives...

Now, where would we find high-density sunlight that could be concentrated to drive a high-efficiency, non-plumbing, non-mechanical, non-PV collector ? Outer-space ? Arizona ? The Sahara ?

Also, if it rectifies broad-band light, a variant should be able to rectify broad-band RF-- Don't Polywells emit such ??

DeltaV
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Post by DeltaV »


Giorgio
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Post by Giorgio »

Thanks! :D

I'll print it and read it during dinner.

ladajo
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Post by ladajo »

And the speed of light is constant in a material
Are you completely sure about that?

Giorgio
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Post by Giorgio »

The paper is extremely interesting, and the claims can be easily tested with actual materials. I am sure that this is what they will do in the coming months.

The math and the logic is also sound. I am quite excited by all the possible applications that can derive by this new way of harvesting light.

Here are some interesting snippets for the ones who do not want to go through it:
Each illuminated atom or molecule thereby acquires a large static
dipole moment, while undergoing driven harmonic motion.
This static polarization can be continuously sustained by
steady illumination and arises from a complex sequence of
events. First, the electric field initiates motion of electrons
from rest, in a direction parallel to the electric field. Then the
magnetic component of the light field causes a deflection of
the electron around its axis. This small deection due to the
Lorentz force grows rapidly in amplitude as the result of a
nonlinear parametric interaction and the average position
of the electron shifts away from the nucleus. The appearance
of this static electric dipole along the axis of propagation is
symptomatic of magnetic energy storage in the medium.
Consequently, these steps result in the formation of an opti-
cally-charged capacitor that has the potential to provide an
efficient source of electrical energy.
............................................................. Also, non-
capacitive schemes may offer alternatives. By using pulsed
or chopped input light, alternative implementations of this
power generation scheme can be imagined that would exploit
the transient, optical magnetization of the medium to pro-
duce current flow inductively.
By passing the light through
an array of conducting split rings whose diameters lie paral-
lel to the propagation axis, single cycle voltage waves would
be generated by each pulse passing through the medium,
according to Lenz’s Law. Designs based on this approach
will be considered in a forthcoming publication.
I skipped from this post all the part about Terahertz generation, but also that part is extremely interesting and is worth to read if you have 30 minutes of time to spare.

ladajo
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Post by ladajo »

I wonder if this can extend to Laser defences?

Giorgio
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Post by Giorgio »

I do not see how, but once the tech is validated I am sure someone will think to applications that we do not even consider right now.

chrismb
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Post by chrismb »

How do you extract useful work from the static electric fields within a dielectric?

If that were possible, surely 'electret batteries' would've been invented years ago?

I don't really buy this, but maybe it is beyond me. Yet another bit of fantasy-tech, or me being thick and not getting it?

Giorgio
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Post by Giorgio »

Doctor William Fisher was kind enough to reply to an e-mail I sent to him asking for a timeline for the experimental validation of the paper.

As expected they should not have issues to validate the process with existing materials and technology.
I am setting up the basic experiments now and hope to begin collecting
data this summer. Depending on the difficulties encountered I hope to
have some results later this year.

William
I'll keep in contact with him and post any new info that he will be kind enough to share.

Giorgio
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Post by Giorgio »

chrismb wrote:How do you extract useful work from the static electric fields within a dielectric?
Is the electric dipole moment presence that stores the work.

In other words, in a capacitor you apply an electric field to a dielectric where its molecules act like dipoles that are free to rotate and line up to the applied electric field.
In this system the dipole moment to the molecules is supplied by the magnetic component of the light.

chrismb
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Post by chrismb »

Giorgio wrote:
chrismb wrote:How do you extract useful work from the static electric fields within a dielectric?
Is the electric dipole moment presence that stores the work. In other words, in a capacitor you apply an electric field to a dielectric where its molecules act like dipoles that are free to rotate and line up to the applied electric field.
In this system the dipole moment to the molecules is supplied by the magnetic component of the light.
I didn't ask where the work done by the mag fields goes - I think you should anticipate I know how a dielectric can store electric energy - I'm asking how you take work from dipoles in a dielectric. It's not like you can just plug in wires or something! And if there is no current flowing, then there is no coupled current. If you were to set up some sort of charge-discharge arrangement with a plate that generates work as it moves up to the thing, discharges and returns to starting point, then you'd only be able to extract work from the surface charges of the material, which'd be not very much at all.

As asked - why don't we have electret batteries, if this is possible?

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