Sorry I worded that badly- I meant that rho and z are perpendicular to each other and when φ = 0 they form the opposite and adjacent sides of a right angled triangle so I could have used a Cartesian coordinate system in the first place (not that the cylindrical and Cartesian coordinates are the...
Thank you for your help! It turns out the problem was that Matplotlib didn't automatically show any contours so I had to define the levels I wanted manually. This is the code I used (I have also changed rho and z to meshgrids):
Re = 6371000
rho1 = np.linspace(-20*Re, 20*Re, 2000)
z1 =...
The Earth's magnetic field is cylindrically symmetric and can be described using cylindrical coordinates, (ρ,z,φ). The components of the magnetic field are given by:
(B_φ) = 0
(B_ρ) = −∂A/∂z,
(B_z) =(1/ρ) * ∂(ρA)/∂ρ.
The vector potential for a dipole field is given by
(A_φ) = (B_e)(ρ) *...