  We demonstrate that Fokker-Planck equations in which spatial coordinates are
treated on the same conceptual level as spin coordinates yield a convenient
formalism for treating magic angle spinning NMR experiments. In particular,
time dependence disappears from the background Hamiltonian (sample spinning is
treated as an interaction), spherical quadrature grids are avoided completely
(coordinate distributions are a part of the formalism) and relaxation theory
with any linear diffusion operator is easily adopted from the Stochastic
Liouville Equation theory. The proposed formalism contains Floquet theory as a
special case. The elimination of the spherical averaging grid comes at the cost
of increased matrix dimensions, but we show that this can be mitigated by the
use of state space restriction and tensor train techniques. It is also
demonstrated that low correlation order basis sets apparently give accurate
answers in powder-averaged MAS simulations, meaning that polynomially scaling
simulation algorithms do exist for a large class of solid state NMR
experiments.
