Plot electric potential distribution

How do I plot electric potential distributions that look similar to this? I have already calculated the Electric potential as a 64x128 matrix (64 electrodes and 128 dipole sources) using V (r, θ)= p*cos(θ)/(4*pi*σ*r^2). I'm just confysed on what commands to use to plot the distriution.

Answer 1

[David Wilson]

Well I kind of get what you want, but you do seem to have a singularity at the origin when r=0.

p = 1; sig = 1; % constants that are still a mystery. 

V = @(r,theta)  min(max(p*cos(theta)./(4*pi*sig*r.^2),-1),1); % Need thresholding here. 

npts = 1000; 
r = linspace(-1,1,npts)'; 
phi = linspace(0,2*pi, npts)';

[R, Phi] = meshgrid(r,phi); 
E = V(R,Phi);  


[X,Y] = pol2cart(Phi,R);
contourf(X,Y,E)
colorbar

and this gives