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 Φ_c calculated by Eq. (19), the crosses indicate numerical turns Φ_num by integrating the magnetic field around the MFR magnetic axis, and the thick black line indicates the straight flux rope Φ_cs based on Eq. (20). The red line represents the distribution of the safety factor q = 1/Φ_c. 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.