We study the small mass limit of the equation describing planar motion of a charged particle of a small mass $mu$ in a force field, containing a magnetic component, perturbed by a stochastic term. We regularize the problem by adding a small friction
of intensity $e>0$. We show that for all small but fixed frictions the small mass limit of $q_{mu, e}$ gives the solution $q_e$ to a stochastic first order equation, containing a noise-induced drift term. Then, by using a generalization of the classical averaging theorem for Hamiltonian systems by Freidlin and Wentzell, we take the limit of the slow component of the motion $q_e$ and we prove that it converges weakly to a Markov process on the graph obtained by identifying all points in the same connected components of the level sets of the magnetic field intensity function.
