Spatial distribution of the dimensionless ﹩\beta =2p/{B}^{2}﹩ and σ = B²/ρ (left panel) from the GRMHD simulation with BHAC, at the late stage of the development of the MRI. The Lorentz factor of the fluid from the GRMHD simulation is also shown (right panel, left half) and compared to that of 10⁶ particles (right half) with q/m = 10⁴, integrated with the modified Hamiltonian method until t = 5.