PDEtool in electrostatic coaxial cable

Hello

I am using PDEtool in electrostatic. I draw a simple geometry with two concentric circle representing a coaxial cable. with C1 radius of 1 and C2 radius of 0.5. Then C1-C2. I mesh it and i input my equation and coefficients in elliptic. epsilon=1, rho=0. My problem is how can i draw the potential or electric field versus the radius of the coaxial cable?

Please help Thanks matt