What causes current to curve like a liquid around an insulator?

[meldraft]

Hey everybody!

Let's say we have an infinite metal plate, and we apply voltage between two points, thus creating a potential. On this plate, we take a cutter and create a finite gap (filled with air), somewhere between the electrodes that apply the voltage.

Simulations in ANSYS show that the current vectors curve around the gap much like a liquid does around an obstacle. Does anyone know the physical effect that causes this? I would speculate that it is a surplus of electrons creating a small charge distribution around the insulator, but I can't see how it fits into Maxwell's equations.

Any pointers would be great!

 

[1994Bhaskar]

It's due to gauss law.by the way where's insulator?it's metal

 

[meldraft]

Hey, thanks for your reply!

The insulator in my case is the air inside the gap. I see how it Gauss' Law describes it, I'm not clear however on what is the actual physical phenomenon.

 

[1994Bhaskar]

gauss law says that inside metal electric field is zero

 

[Gordianus]

The charge at the interface metal-air buids up an electric field that deflects the electrons around the gap (we know current can't flow trough the gap). When we applied the voltage, for a very short time, current flow was "undisturbed". Once some charge piled up at the interface, the resulting electric field makes the electrons move around the cut.

 

[meldraft]

Yes, this makes sense of course. This conversation also helped my googleing, so I found the effect, it's called polarization:

http://en.wikipedia.org/wiki/Electric_polarization

Thanks a lot for your replies!

 

[chrisbaird]

I don't think material polarization has anything to do with it. You could repeat the experiment with vacuum in the gap instead of air and still get the same result. It is because of the interaction of charges as they flow.

 

[meldraft]

What I was thinking is that the boundary around the gap gets polarized. Is this not a good interpretation?