Plot radial and tangencial components

Hello,

I need some help about the results of a cylindrical motor.
I have a cylindrical motor defined in 2D. I have defined the cylindrical system "sys2", and now i want to see the radial and tangential components of the magnetic induction field on the middle of the airgap.
How can I plot, for example, the tangential component of the magnetic field on a 1D-plot?

There is any expression for it? (like rmm.Bphi, instead of rmm.BX?)

Thanks for you attention,
The best regards,
João Fernandes