Why Isn't My Debye Medium Wave Simulation Producing Expected Results?

[lemoz]

Frequency dependent material simulation

 

[berkeman]

Welcome to PF.

What have you found in your Google searching so far? What frequency range do you need to simulate? What do you mean by "one dimension"? Can you show a sketch of the setup that you want to simulate?

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[lemoz]

Ok. I will try to be more explicit. I try to simulate a debye the propagation of electromagnetic wave in a debye medium with this code below. But i have trouble, i don’t have expected result and i don’t wich is the problem. I think that the absorbing boundary condition don’t work correct lu.

[Mentor Note: pasted your Word document code into the code box below]

Program debyeformulation;
Const
    size=200;
Var
     dz: array[0..size-1] of real;
     ez: array[0..size-1] of real;
     hx: array[0..size-2] of real;
     ga: array[0..size-1] of real;
     gb: array[0..size-1] of real;
     gc: array[0..size-1] of real;
     ix: array[0..size-1] of real;
     sx: array[0..size-1] of real;
     Time,maxTime,i:integer;
     dx,dt,epsz,epsilon,sigma:real;
     t0, spread, pulse:real;
     tau,hi ;
     ezl1,ezl2,ezh1, ezh2:real;
     monfichier:text;
begin
     assign(monfichier,'debyeformul100.txt');
     rewrite(monfichier);
     dx :=0.01; dt:=dx/6e8; epsz:=8.8e-12;
     for i:=0 to size-1 do
     begin
            ga[i]:=1.0; gb[i]:=0.0; gc[i]:=0.0; dz[i]:=0.0; ez[i]:=0.0; hx[i]:=0.0; ix[i]:=0.0; sx[i]:=0.0;
     end;
     
     ezl1:=0.0;  ezl2:=0.0; ezh1:=0.0; ezh2:=0.0;
     epsilon:=2.0; sigma:=0.01; hi:=2.0; tau:=0.001;
     for i:=100 to size-1 do
     begin
            ga[i]:=1.0/(epsilon+sigma*dt/epsz+hi*dt/tau);
            gb[i]:= sigma*dt/epsz;
            gc[i]:= hi*dt/tau;
     end;
     for i:=0 to size-1 do
     begin
           writeln(i,'',ga[i]:6:2,'',gb[i]:6:2,'',gc[i]:6:2);
     end;
    maxTime:=100; t0:=50.0; spread:=10.0;
    for Time:=0 to maxTime-1 do
    begin
          for i:=1 to size-2 do
          begin
                dz[i]:=dz[i]+0.5*(hx[i-1]-hx[i]);
          end;
              pulse:=exp(-0.5*(Time-t0)*(Time-t0)/spread);
              dz[5]:=dz[5]+pulse;
          for i:=1 to size-2 do
              begin
                     ez[i]:=ga[i]*(dz[i]-ix[i]-sx[i]);
                     ix[i]:=ix[i]+gb[i]*ez[i];
                     sx[i]:= exp(-dt/tau) *sx[i]+gc[i]*ez[i];

              end;
             ez[0]:= ezl2;
             ezl2:= ezl1;
             ezl1:= ez[1];
             ez[size-1]:= ezh2;
             ezh2 :=ezh1
             ezh1 :=ez[size-2] ;
             for i:=0 to size-1 do
             begin
                  hx[i]:=hx[i]+0.5*(ez[i]-ez[i+1]);
             end;

      end;
      for i:=0 to size-1 do
      begin
            write(monfichier,i,' ',ez[i]:1:3);
            writeln(monfichier);
      end;
         close(monfichier);
      readln;
end.