Fail to plot electric field lines in a neBEM geometry

[gtsileda]

microb2.C (3.7 KB)

Dear experts,

Please have a look at the attached code and picture. I built a neBEM example in garfield++ that I used in past with the standalone version. The left and top central plot are obtained with the garfield++ code I provided, while the bottom central and right plot with the standalone garfield.
I would like to have superimposed on the left plot the electric field lines as shown on the bottom central plot. I am getting when I execute it: ViewField::EqualFluxIntervals:
** The flux changes sign over the line.**
Could you please have a look?

Thanks a lot in advance

Georgios

[bellenot]

I am adding @hschindl in the loop.

[hschindl]

Hi Georgios,
thanks for your message and apologies for the delay in getting back to you.

I managed to get a plot showing both the contours of the potential and the field lines using the piece of code below (essentially the same as yours):

  ViewField fieldView(&nebem);
  fieldView.SetPlane(0, -1, 0, 0, 0, 0);
  fieldView.SetArea(-0.01, -0.01, 0.0, 0.01, 0.01, 0.01);
  fieldView.SetNumberOfContours(10);
  fieldView.PlotContour();

  std::vector<double> x1;
  std::vector<double> y1;
  std::vector<double> z1;
  fieldView.EqualFluxIntervals(-0.008, 0., 0.007, 0.008, 0., 0.007,
                               x1, y1, z1, 15);
  fieldView.PlotFieldLines(x1, y1, z1, true, false);

I had to reduce the number of periodic copies though to get a result in a reasonable amount of time.

Just a small comment: instead of using a finite thickness for the anode plane and drift plane, you could set the thickness to zero. This will reduce the number of surface panels and elements.

[gtsileda]

Thank you so much!
Following your suggestion I decreased the periodic copies from 10 to 2, and it works fine!

Best regards

Georgios