From: heathjohn2@gmail.com   
      
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   On Sunday, March 5, 2017 at 2:55:56 AM UTC-5, Roland Franzius wrote:   
   > Am 03.03.2017 um 10:04 schrieb John Heath:   
   > > I like it. Simple and do-able. Should   
   > > be able to swing a 3 foot wire at 3 or   
   > > 4 Hz by hand with the hand end of the   
   > > wire clamped to a scope. I have spectrum   
   > > lab audio analyzer software on a lap top   
   > > for VLF whistlers , moving sky charges.   
   > > With this most of what is needed is already   
   > > in place. As you have already done this I   
   > > can proceed with confidence. One concern.   
   > > Standing in the middle of no where spinning   
   > > a 3 foot wire while looking at a lap top could   
   > > draw unwanted attention. I am tested for   
   > > a better WIFI connection officer , that's   
   > > my story and I am sticking to it.   
   > >   
   > > As to your dislike of the Lorentz contraction   
   > > interpretation of magnetism you are not alone.   
   > > I can say from my shoes it grows on you   
   > > over time. How often is there an opportunity   
   > > to toss a fundamental force in nature such   
   > > as magnetism straight into the trash bin?   
   > > One less to worry about.   
   > >   
   >   
   >   
   > Don't, because there are genuine electric and magnetic fields.   
   >   
   > The two quadratic forms E^2-B^2 and E.B are invariant with respect to   
   > Lorenz transformations. E.B=0 and |E|=|B| is mainly radiation.   
   >   
   > So there are static fields with |E|>|B| which are predominantly electric   
   > fields because you can find a system of reference with B'=0 and E' =   
   > E/sqrt(1-(v/c)^2).   
   > This system can be thought to be the rest system where you see charges   
   > at rest producing their common Coulomb field.   
   >   
   > And there are predominantly magnetic fields |B|>|E| where you can find a   
   > system reference with E'= 0 and B' = B/sqrt(1-(v/c)^2)   
   >   
   > Taken cum grano salis of course, because E,B are components of a rank 2   
   > tensor field, transforming with the product of two Lorentz tranformation   
   > matrices.   
   >   
   > An example of pure magnetic field with E=0 everywhere is the cylindrica=   
   l=   
   >   
   > magnetic field B_phi =1/r around a finite conducting wire with with two   
   > equal constant currents: one of the negative charges to the left and   
   > positive charges to the right of identical current and charge density.   
   >   
   > So as an experiment, move at constant speed with your synchronized   
   > clocks/meterstick/ampere-meter/volt-meter equipment along a wire with   
   > the half velocity v/2 of the electron current.   
   >   
   > Now you have two equal currents of negative electrons and positive ions   
   > with equal but opposite velocities +-v/2.   
   >   
   > The wire is assumed somehow to be electrical neutral in the rest system   
   > of the ions.   
   >   
   > Of course, there will be a small longitudinal electrical field E_z to   
   > drive the electric current against the resistivity and to supply by ExB   
   > the dissipation energy current density from the field outside into the   
   > wire.   
   >   
   > E_z and dissipation can be made very small or even zero for a   
   > superconductor. So we can neglect the dissipation problem in a first   
   > approximation.   
   >   
   > Now you have by the Lorenz formula   
   >   
   >   B'_phi = B_phi /Sqrt(1-(v/2c)^2)   
   >   
   > and   
   >   
   > E'_r = v/(2c) x B_phi / Sqrt(1-(v/2c)^2)   
   >   
   > which means that in this system the current is larger and the wire is   
   > not neutral but - as an ideal conductor - carries some surface charge   
   > density  D_r that, by definition, is the value of D_r at the surface.   
   >   
   > How does this happen?   
   >   
   > Lorentz contraction contracts the longitudinal measured distance of the   
   > ions from rest at v=0 to v/2 using the simultaneity of the moving   
   > clocks.  By the same argument the distance of electrons is enlarged   
   > because their velocity is reduced from v to v/2. So the net charge   
   > density varies linearly with v.   
   >   
   > This fundamental effect arises at velocities as small as the current   
   > velocity of electrons of order 10^-11 lightseconds/second for a current   
   > of 1 A at a density of some 10^27 m^-3.   
   >   
   > The gigantic particle density of charges moving freely in metallic   
   > conductors makes these macroscopic effects easily detectable and   
   > measureable with high precision. This simple fact enabled Gauß, Farad=   
   ay   
   > Maxwell and Einstein to find the laws of electrodynamics.   
   > These laws, applied by the gauge of the 4-momentum, imply Lorentz   
   > invariance of all physical laws.   
   >   
   > --   
   >   
   > Roland Franzius   
      
   Two equal + and - charges in opposite directions with equal velocities. Let=   
    us place two such wires next to each other. The electron of one wire sees =   
   the other electron in the other wire as non relativistic as they are both m=   
   oving in the same direction. However the electron see the positive charge i=   
   n the other wire as length contracted time 2 as they are both moving in opp=   
   osite directions. This would lead to a strong Coulomb attractive force from=   
    a Lorentz contraction point of view. Your example of + and - charges has s=   
   ymmetry but that charge symmetry is lost from the FoR of the individual mov=   
   ing charge. The Lorentz contraction interpretation of a magnetic force woul=   
   d not be taught in colleges without first raking it over to make sure it ge=   
   ts the right answer. To give this balance this does not means it is true. I=   
   t only means it gets the right answer.   
      
   I would add that a current of 1 amp in a copper wire to the right is equiva=   
   lent to physically moving the same wire to the left at the same speed as th=   
   e electron current is moving right. Now the electrons are not moving but th=   
   e protons are in the opposite direction so it all equals out. The reason I =   
   bring this up is net electron cloud velocity in a 18 gauge wire at 1 amp is=   
    only a few m meters per second. Surprisingly slow for relativistic effects=   
   .   
      
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