A three-dimensional implicit particle-in-cell (iPIC3D) method implemented by S. Markidis et. al. in [“Multiscale simulations of plasma with iPIC3D”, Mathematics and Computers in Simulation, 80(2010), 1509-1519] allows time steps at magnetohydrodynamics time scale. The code requires the solution of two linear systems: a Poisson system related to divergence cleaning, and a system related to a sec...