The “Helical Flux Rope tube” opposite is the confinement of plasma in a defined volume with uniform rotation around the central axis of a magnetic field. The systems volume is at entropy when considered as a straight cylindrical tube, however due to the geometry of the curve of the tube around the second poloidal axis (D in image opposite with the axis projecting into the screen from our position).
If 1/2D = R to central axis, then the compression of potential energy on the inside curve must produce a Cartesian Oval in the 2 dimensional cross section of the flux tube at any cross section of the curve.
The direction of rotation on the inside of the curve is uniform in the Z axis of the Plasmoid and this produces a merging wave that is equal and no longer opposite due to the change in direction of current in the flux tube loop around the axis.
The Current sheet generated in an elongated Plasmoid is compressed into a Z-Pinch as the geometry of the Plasmoid breaks at the compression point to form a toroidal geometry around the Poloidal axis as the final disconnection from the larger field happens triggering the reconnection of the plasmid into a Toroid. As the toroid density increases due to confinement, the pressure on the Z-pinch also increases and current velocity increases with Potential difference between Negative and Positive Z that formed the Helical Poloidal current tube from the current sheet of the elongated Plasmoid.