# Harmonic dependence of magnetic field and scalar potential

we shall now consider the special case when 'the scalar potential' and the field component depend harmonically on the $$z$$ coordinate (along a steady magnetic field), i.e., when 'scalar potential' and the fields contain one of the following functions (or a linear combination of them)
$$\exp(i\beta z)$$, $$\exp(-i\beta z)$$, $$\sin(\beta z)$$, $$\cos(\beta z)$$.