Timeline for Does alternating current (AC) require a complete circuit?
Current License: CC BY-SA 4.0
26 events
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| May 7, 2018 at 9:41 | history | edited | Nat | CC BY-SA 4.0 |
deleted 186 characters in body
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| Mar 9, 2015 at 0:09 | comment | added | Selene Routley | @HDE226868 Hmmm. Dubious honour! | |
| Mar 8, 2015 at 21:05 | comment | added | HDE 226868 | I believe this is currently the longest answer on Physics (data.stackexchange.com/physics/query/edit/284013 - Not my query) | |
| Sep 20, 2013 at 21:24 | vote | accept | BlueRaja - Danny Pflughoeft | ||
| Aug 29, 2013 at 16:04 | history | bounty ended | BlueRaja - Danny Pflughoeft | ||
| Aug 29, 2013 at 16:04 | vote | accept | BlueRaja - Danny Pflughoeft | ||
| Sep 20, 2013 at 21:24 | |||||
| Aug 29, 2013 at 5:49 | comment | added | user6972 | When I look at this question, I think that on a human scale it would be a gigantic power generator between the two planets. Earth with a strong magnetic field, high atmospheric energy from friction (lightening being the most spectacular example), more solar EM energy and large seismoelectromagnetics connected to mars which would have much lower of all these things. | |
| Aug 28, 2013 at 23:56 | comment | added | Selene Routley | ...that go with things like TEM exploration (I think the acronym means "terrestrial electromagnetic") and resistivity tomography do work remarkably well over many kilometer scales simply assuming simple $\sigma$, $\mu$ and $\epsilon$ fields ("well" in the sense that what's duggen up afterwards in mining works is not much of a surprise). | |
| Aug 28, 2013 at 23:54 | comment | added | Selene Routley | @user6972 It is actually a good question that does go well beyond the present one and it seems, from my own quick reading around the web, that there are whole highly nontrivial branches of Earth Science devoted to this kind of thing such seismoelectromagnetics. Not only will there be conductivity $\sigma(\mathbf{r})$, electric and magnetic constant fields $\epsilon(\mathbf{r})$, $\mu(\mathbf{r})$I characterizing the planets, but there are also seismoelectric sources (giant AC piezoelectric sources). I do know, however, from work I did many, many years ago that the inverse scattering methods... | |
| Aug 28, 2013 at 19:36 | comment | added | user6972 | I appreciate your great answer on how EM waves work without a conductive return path. I guess my point is this can be a huge value just between peaks and valleys on earth, so with this much charge motion on the surface of a conductor, along with charge deposited from the sun/magnetic field/atmospheric frictional charges plus motion of spinning the wire through a magnetic field that the real answer is quite complex but saying "you have to solve the full Maxwell equations" should cover it. ;-) | |
| Aug 28, 2013 at 15:06 | comment | added | Selene Routley | @user6972 Sorry, in the simplified TEM analysis, I should have said that the charge is defined by Eq (29), not Eq (19). | |
| Aug 28, 2013 at 4:17 | comment | added | Selene Routley | @user6972 ... characterize each planet by a varying conductivity field $\sigma(\mathbf{r})$ and then solve Maxwell's equations to find an EM field in keeping with (9) for this conductivity field. "Dynamic electro static charge" is not only present in the general case on the planets by the way: propagation delays beget the same current bunching on the wires ("what goes in must either stay in or come out: nothing goes missing"); in the simplified TEM analysis, it is described by Eq (19). In general, you have to solve the full Maxwell equations: you can't just think circuits and antennas. | |
| Aug 28, 2013 at 4:16 | comment | added | Selene Routley | @user6972 "dynamic electro static charge" = source of the electric component $\phi_B + \phi_C$ of the potential 4-vector as described in Eqs (1) and (11). "dynamic electro static charge" is the term $\partial_t \rho$ in the total current, i.e. the divergence of the displacement current. It arises whenever the conduction currents "bunch up" or "spread out". Simplistically, I have conceptualized this "dynamic electro static charge" on the planets as charges on their surfaces, as will happen if they are goodish conductors i.e. $\sigma \gg \omega \epsilon$. More generally, you have to .... | |
| Aug 28, 2013 at 3:10 | comment | added | user6972 | While this more than covers the use of the planets as antennas...what about the complexity of each planet having it's own dynamic electro static charge? | |
| Aug 26, 2013 at 23:31 | comment | added | Selene Routley | @PaulWagland Thanks, see comment to Wilhelmsen above if you're interested | |
| Aug 26, 2013 at 23:30 | comment | added | Selene Routley | @Wilhelmsen If you're interested, you might like to takle Maxwell's work "A Treatise on Electricity and Magnetism" which, 140 years later, is still remarkably readable and clear. Volume 2 of "The Feynman Lectures on Physics" also has excellent descriptions of electromagnetism. | |
| Aug 26, 2013 at 21:32 | comment | added | chwi | How can I upvote this to infinity? | |
| Aug 26, 2013 at 20:58 | comment | added | Paul Wagland | Just when I thought the internet couldn't get any more awesome… | |
| Aug 26, 2013 at 6:14 | comment | added | Selene Routley | @BlueRaja-DannyPflughoeft Just added so more intuitive discussion and picture in the theoretical overview. | |
| Aug 26, 2013 at 6:13 | history | edited | Selene Routley | CC BY-SA 3.0 |
Fixed links
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| Aug 26, 2013 at 4:00 | history | edited | Selene Routley | CC BY-SA 3.0 |
Added divergence current picture and more intuitive, thorough explanation of Maxwell's displacement current postulate
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| Aug 24, 2013 at 12:47 | history | edited | Selene Routley | CC BY-SA 3.0 |
Better description of TEM
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| Aug 23, 2013 at 13:57 | history | edited | Selene Routley | CC BY-SA 3.0 |
Fixed "before Maxwell" ampere law
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| Aug 23, 2013 at 13:13 | history | edited | Selene Routley | CC BY-SA 3.0 |
Added circuit interpretations
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| Aug 23, 2013 at 3:54 | history | edited | Selene Routley | CC BY-SA 3.0 |
Changed fundamental description
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| Aug 23, 2013 at 3:44 | history | answered | Selene Routley | CC BY-SA 3.0 |