Fig. 1

Schematic illustrations of the radial frozen-flux SV mechanisms. a Tangential advection. b Tangential stretching. c Radial advection. d Radial stretching. The solid lines represent the initial configuration at time t _o , and the dashed lines represent an evolved configuration due to the fluid flow action after some time δt. The lines represent either radial field contours (a and b) or magnetic field lines (c and d). Spatial orientations are given at the bottom left of each subplot