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The Maxwell's wave equation have the term c = 1/sqrt(mu*epsilon) (1) where c is the speed of the electromagnetic wave, as function of mu (magnetic permeability) and epsilon (electric permitivity) of the medium (mu=mu0*mur, epsilon=epsilon0*epsilonr).
In his equations, Maxwell predicted electromagnetics
waves traveling at speed c.
Whit mu=mu0 , epsilon=epsilon0 (vacuum) c=299 792 458 m/s. Nice!, c calculated from static constants !
Looking to magnetic field equation, B=mu*H, we can see that mu can be altered, saturating magnetically the medium. If the medium is saturated, B is not a linear function of H anymore, and mu=B/H. The "constant" mu decreases as the saturation increases [link]. This effect is used to get variables inductances, changing mu in this way.
So, we can expect that c' > c, with c' = (1) with mu=mu' for a magnetically saturated medium.
So, a transmision line made of a magnetic saturated material could travel faster than vacuum light speed; resulting in ultra high speed communications, ultra high speed computers, etc.
I don´t expect to be correct, but is nice to play with natural constants :-)
Saturation
http://en.wikipedia...tion_%28magnetic%29
[piluso, Nov 28 2012]
Mu towards zero:
http://books.google...0saturation&f=false
[piluso, Nov 28 2012]
That's not the only way
Faster_20Than_20Light
Light-speed depends on the properties of space-time, as you noted. And more than one of those properties are adjustable. [Vernon, Nov 28 2012]
[link]
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Interesting idea, but I see two flaws. |
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1) Are there any materials that experience magnetic sauration (like iron, nickle, etc.) that are transparent? |
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2) From the same link: "...relative permeability increases with H to a maximum, then as it approaches saturation inverts and decreases toward one." so even when saturatated, mu of any ferromagnetic material is always greater than mu of a vaccuum. |
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There are some materials with mu less than vacuum. Those are diamagnetic materials like aluminum, water, bismuth and superconductors, but I don't know of any that don't have a permitivity (epsilon) that is very large. Threoretically a superconductor has mu=0 and epsilon=infinity, so it's kind of hard to calculate the speed of light in a superconductor using Maxwell's equations. When I searched for "speed of light in a superconductor" I found this very informatinve statement: |
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// Photons inside a superconductor actually get a mass from the abelian Higgs mechanism. This phenomenon was actually discovered by Anderson and the later work by Higgs and others was about generalizing it to relativistic and nonabelian gauge theory. What happens is essentially that Cooper pairs behave like a scalar field with a nonzero vacuum expectation value. The U(1) gauge symmetry is broken and the would-be Goldstone boson adds to the 2 photon degrees of freedom to complete a massive vector field. // |
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Yeah, that's how I would explain it :) Can someone tell me if that statement actually makes sense and isn't just a bunch of pseudojargon strung together that is supposed to sound impressive? |
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There is no need for transparency, I'm using the term speed of light as general form of speed of electromagnetic wave. |
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// From the same link: "...relative permeability increases with H to a maximum, then as it approaches saturation inverts and decreases toward one."// |
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The reference [3] [link] of this paragraph in Wikipedia is a link to ebook that said: |
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"But in saturation region the value of mu relative falls down to very low value as slope of B-H curve in saturation region is almost zero." |
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Seems to me that the editor of the article in Wikipedia made a mistake here (no!, horror!!!) so, mu relative decreases toward zero, not one. |
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//I found this very informative statement: .....//
I will need about 6 years of extra physics to understand the basics to refute this point.
In defense of my statement, I can say that is short, elegant, and may be mathematically correct :-) |
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//Maxwell's wave equation have the term...// |
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Hey, don't blame me. I voted for a simple "Speed of
light = 1 in any units" theory. This leads to an
alternative formulation of relativity in which
Imperial units are a preferred frame of reference,
and the kilometre (a dastardly French invention)
becomes variable. |
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1) Okay, I can agree that transparancy isn't important. |
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2) Hmm, I flagged that because of my previous understanding of saturation as well as that quote. Note that reference [3] says the slope is "almost 0" not that it approaches 0. Compared to the the magnitude when not saturated, 1 may be considered to be almost 0 for most practical purposes of building motors and such. The title of the book _Basic_Electrical_Engineering_ tells me that the concepts may be somewhat simplified, and reference [2] _Ferromagnetism_ which I can't find online might include more detailed info that the editors used (or maybe not). I notice on the "talk" tab of the Wiki page that the article actually originally stated that it decreased towards 0, but that was changed to be 1. However that change was made based on the knowledge of a contributor and the editor, not referencing any specific source. |
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My understanding is that the "boost" in permeability provided by iron comes from the dipoles alighning. Once all are alligned, the "boost" goes away, but by superposition, the increase in field strength that would occur in a vacuum still occurs. Actually I would not be surprised if the relative permeability during extreme saturation could get slightly below 1 since, once saturated, ferromagnetic materials may have some of the same properties as diamagnetic materials, but you might not find that level of detail in an undergrad level textbook. |
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You are right, see the point now. The increase of speed of light speed must wait :-) |
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Magnetic saturated "material", as in the space-time fabric!
Reverse Ion Drive! |
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Too many apples, not enough oranges... |
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//first rays of the sun on midsummer's day a couple
of hours early// The limit, shirley, would be about 8
minutes? |
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The sun is further away at the winter solstice, as any fule kno. |
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Well that's where you're wrong. It's the Earth that's
further away. |
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// Photons inside a superconductor actually get
a mass from the abelian Higgs mechanism.// Good for
photon sails ? |
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I recently read that magnetic effects are limited to c. |
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