Temporal evolution of the magnetic field configuration (upper panel) and plasma β parameter (lower panel) up to the quasi-stationary final configuration. The initial magnetic field is uniform with a value of 30 G. The external mass transfer rate is 10¹⁶ g cm⁻². The dashed black line in the upper panel gives the theoretical expected slope of the magnetic field, in R^−5/4 deduced from Eq. (23). The dotted black line in the lower panel gives the value of β_eq.