  Numerical simulations of the force-free magnetodynamics (FFMD) of the
electromagnetic field around a spinning black hole are useful to investigate
the dynamic electromagnetic processes around a spinning black hole, such as the
emergence of the Blandford--Znajek mechanism. To reveal the basic physics of
magnetic fields around a black hole through the dynamic process, we use
one-dimensional (1D) FFMD along the axisymmetric magnetic surface, which
provides a relatively simple, sufficiently precise, and powerful tool to
analyze the dynamic process around a spinning black hole. We review the
analytic and numerical aspects of 1D FFMD for an arbitrary magnetic surface
around a black hole. In addition, we also show some numerical simulation test
results for three types of magnetic surfaces at the equatorial plane of the
black hole.
