Transmission Line (shielded dual stripline )
It's a little hard to see the direction arrows on your plot, and you haven't explicitly stated what applied potential is on the center strips.

So I'm guessing, but it looks like both strips have 1V applied, the outer shield is grounded (0V), and the arrows are pointing into the strips.  If that is true, then the field lines are not pointing in the correct direction.

The electric field in the transverse plane still obeys $$ E=-\nabla \phi ,$$ so the field should point generally from the high-potential strip lines to the outer ground shield when the strip lines have a positive potential applied.