(Solved): A magnetic mirror configuration as shown in the figure is maintained with an axial magnetic field ...

A magnetic mirror configuration as shown in the figure is maintained with an axial magnetic field \( B(z)=B_{0}\left(1+k z^{2}\right) \), where \( k \) is a constant. Determine the reflectin point (aka "mirror point") \( z_{m} \) for an electron with velocity \( v \) initially at \( z=0 \) with an initial pitch angle \( \theta_{0} \).