  Heliospheric plasmas require multi-scale and multi-physics considerations. On
one hand, MHD codes are widely used for global simulations of the
solar-terrestrial environments, but do not provide the most elaborate physical
description of space plasmas. Hybrid codes, on the other hand, capture
important physical processes, such as electric currents and effects of finite
Larmor radius, but they can be used locally only, since the limitations in
available computational resources do not allow for their use throughout a
global computational domain. In the present work, we present a new coupled
scheme which allows to switch blocks in the block-adaptive grids from fluid MHD
to hybrid simulations, without modifying the self-consistent computation of the
electromagnetic fields acting on fluids (in MHD simulation) or charged ion
macroparticles (in hybrid simulation). In this way, the hybrid scheme can
refine the description in specified regions of interest without compromising
the efficiency of the global MHD code.
