x = np.linspace(-15, 15, 100)
z = np.linspace(-5, 5, 100)

fig, ax = plt.subplots(1, 1, figsize=(12, 4))
pot.plot_contours(grid=(x, 1.0, z), ax=ax)
ax.set_xlabel("$x$ [{}]".format(pot.units["length"].to_string(format="latex")))
ax.set_ylabel("$z$ [{}]".format(pot.units["length"].to_string(format="latex")))
fig.tight_layout()