dielectric

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{  DIELECTRIC.PDE

 

   This problem shows the electrostatic potential and the electric field

   in a rectangular domain with an internal region in which the dielectric

   constant is fifty times that of the surrounding material.

   The electric field E is -grad(V), where V is the electrostatic potential.

   

   See also FIELDMAP.PDE

}

title 'Electrostatic Potential'

variables V

definitions

 eps = 1

equations

 div(eps*grad(V)) = 0  

boundaries

region 1

  start (0,0)

  value(V) = 0   line to (1,0)

  natural(V) = 0 line to (1,1)

  value(V) = 100 line to (0,1)

  natural(V) = 0 line to close

region 2

   eps = 50

  start (0.4,0.4)

  line to (0.8,0.4) to (0.8,0.8)

        to (0.6,0.8) to (0.6,0.6)

        to (0.4,0.6) to close

monitors

contour(V) as 'Potential'

plots

grid(x,y)

contour(V) as 'Potential'

vector(-dx(V),-dy(V)) as 'Electric Field'

end