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

1. Aug 30, 2011

### 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!

2. Aug 30, 2011

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

3. Aug 30, 2011

### meldraft

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.

4. Aug 30, 2011

gauss law says that inside metal electric field is zero

5. Aug 30, 2011

### 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.

6. Aug 31, 2011

### meldraft

7. Aug 31, 2011

### 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.

8. Aug 31, 2011

### meldraft

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