  A finite Larmor radius approximation is derived from the classical Vlasov
equation, in the limit of large (and uniform) external magnetic field. We also
provide an heuristic derivation of the electroneutrality equation in the finite
Larmor radius setting. Existence and uniqueness of a solution is proven in the
stationary frame for solutions depending only on the direction parallel to the
magnetic field and factorizing in the velocity variables.
