From: jos.bergervoet@xs4all.nl   
      
   On 3/5/2017 6:49 PM, Rich L. wrote:   
   > There are actually two ways to do EM: by electric and magnetic fields   
   > using Maxwell's equationa or by summing the electromagnetic 4-potential   
   > (with Lorentz transforms for moving charges) for all charges in the   
   > system (both free and bound).  The former approach involves working with   
   > a 2nd rank EM field tensor while the latter involves only a single rand   
   > tensor (a 4-vector).   
   >   
   > The brilliant thing about the Maxwell approach is that you don't have to   
   > know the distribution and motions of the bound charges (in dielectrics   
   > and metals) as you can use simple boundary conditions to get approximate   
   > solutions that are quite good in almost all practical cases.  The   
   > 4-potential approach requires you to solve for all the bound charge   
   > densities and motions, which you can't do without knowing the fields,   
   > which you can't know without knowing the bound charge distributions...   
   > This is not a problem in principle, but is a big problem for practical   
   > calculations.   
      
   Still, you can use either Hallén's or Pocklington's method with good   
   results for simple conducting wires or planes. Isn't that the choice   
   of methods you are referring to?   
      
   --   
   Jos   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)