Discussion Forum

Dear Comsol Users
For learning reasons, I have calculated the classic electric field of a 2d dipole. Maybe it is useful for other to know how i did it.
First, I defined two solid circles, for which I wanted to assign a surface charge density of +q/m^2 and -q/m^2. However, this was not possible until I defined an area, where the circles where placed in. So I placed said charges on either circle, and put the enclosing square to zero potential. I thought I could now solve the electrostatic problem, but I received an error message telling me that I need to assign relative permittivity of the circles. I am not interested in the field with in the charges (whatever that might look like) so I performed a geometrical operation being to subtract the circle areas of the surrounding square area. Then I assigned a relative permittivity of 1 to the square area, making it essentially vacuum.
Now I could solve the electrostatic problem and plot the electric potential together with the electric field (see attached figure).
picturepush.com/public/9074172
I would like to ask if this is the recommended way of doing these kind of basic problems. One thing I wonder about is how I can change the plotting of the electric field such that the arrows do not reach into the circles (where there is essentially "nothing"). How do I do that? I tried setting the arrow base to tail, but then they just reach into the other circle.

Thanks for comments.