More details about the initial magnetic structure of refTDb shown in Fig. 1. Panel a: magnetic field lines of the configuration in Fig. 1 projected on zx-plane. Panel b: twist turns of magnetic field lines obtained by different methods; the solid black line indicates Φc calculated by Eq. (19), the crosses indicate numerical turns Φnum by integrating the magnetic field around the MFR magnetic axis, and the thick black line indicates the straight flux rope Φcs based on Eq. (20). The red line represents the distribution of the safety factor q = 1/Φc. Panel c: internal toroidal (blue), poloidal (green), and total current (black) distribution of the MFR along the z-axis. Panel d: internal toroidal for α = 1 (blue) and α = 0 (blue dashed), and the poloidal (green) magnetic field strength of the MFR along the z-axis; a cross and a circle indicate the position of the magnetic axis and geometry axis of the MFR, which indicates a Shafranov shift.