Oscillation of the torus centre R = R_c (top panel; radius is expressed in geometrized units GM / c² on the vertical axis), and of the central density ρ = ρ_c (bottom panel); density is relative to its peak value at the centre, ρ_c = ρ(R_c). The solid line is for a non-magnetized case (β ≫ 1), the dotted line denotes the magnetized configuration (β = 3).