Could the longitudinal displacement be instantaneous, while the transverse is limited to C?
There reminds me of a conundrum that occurs with magnetic fields especially if one does not consider vector analysis. If a current is passed through a large hoop coil suddenly (current quickly reaching a steady state), when does the magnetic field reach maximum at the center? Since all lines are closed loops that pass through the center of the coil, and since this also applies to even the most slight and distant magnetic influence then there are 3 possibilities. Either the magnetic field is instantaneously established everywhere, this would make sense if the electric field were instantaneous. Or the magnetic field in the center (despite constant current) never quite reached an absolute maximum since the field continues to expand, however minimally. Or the magnetic field in the center is manifested fully before the external field is, which means we have open lines of magnetic flux in the center of a magnet. I am not sure if this seem so interesting if the convenient lines of force is dropped for a more accurate vector analysis model. John On Sat, Feb 15, 2014 at 7:44 PM, H Veeder <hveeder...@gmail.com> wrote: > Here is a November 2012 paper about an experiment which tentatively shows > that electric fields seem to propagates rigidly, i.e. with infinite speed. > Although it hasn't been published in a peer reviewed journal yet, given the > fact that the observation challenges Special Relatively, one would have > expected this paper to zip around the blogosphere and make its way into > mainstream media. Perhaps the recent mistaken claim of faster-than-light > neutrinos at a noteworthy facility - namely CERN - has dampened interest in > such challenging observations. > > Harry > > -------------- > > http://arxiv.org/abs/1211.2913 > > Measuring Propagation Speed of Coulomb Fields > > A.Calcaterra, R. de Sangro, G. Finocchiaro, P.Patteri, M. Piccolo, G. > Pizzella > (Submitted on 13 Nov 2012) > > Abstract > The problem of gravity propagation has been subject of discussion for > quite a long time: Newton, Laplace and, in relatively more modern times, > Eddington pointed out that, if gravity propagated with finite velocity, > planets motion around the sun would become unstable due to a torque > originating from time lag of the gravitational interactions. > Such an odd behavior can be found also in electromagnetism, when one > computes the propagation of the electric fields generated by a set of > uniformly moving charges. As a matter of fact the Li\'enard-Weichert > retarded potential leads to a formula indistinguishable from the one > obtained assuming that the electric field propagates with infinite > velocity. Feynman explanation for this apparent paradox was based on the > fact that uniform motions last indefinitely. > To verify such an explanation, we performed an experiment to measure the > time/space evolution of the electric field generated by an uniformerly > moving electron beam. The results we obtain on such a finite lifetime > kinematical state seem compatible with an electric field rigidly carried by > the beam itself. > > > Conclusions > Assuming that the electric field of the electron beams we used would act > on our sensor only after the beam itself has exited the beam pipe, the L.W. > model would predict sensors responses orders of magnitudes smaller than > what we measure. The Feynman interpretation of the Li enard-Weichert > formula for uniformly moving charges does not show consistency with > our experimental data. Even if the steady state charge motion in our > experiment lasted few tens of nanoseconds, our measurements indicate > that everything behaves as if this state lasted for much longer. > > To summarize our fi nding in few words, one might say that the data > do not agree with the common interpretation of the Li enard-Weichert > potential for uniformly moving charges, while seem to support the idea of > a Coulomb field carried *rigidly* by the electron beam. > We would welcome any interpretation, diff erent from the Feynman > conjecture or the instataneous propagation, that will help understanding > the time/space evolution of the electric field we measure. >
