Published online by Cambridge University Press: 04 August 2017
A magnetodynamic mechanism of jet formation, in which a packet of the toroidal component of the magnetic field Bϕ plays a role, is proposed. Such a packet of toroidal field, produced by the rotational motion in the β=Pg/Pm≫1 region, relaxes itself in the β≪1 region when brought up into such a region, for example, by the process of flux emergence due to magnetic buoyancy. In the β≪1 region, a progressive pinch is caused by this relaxation and the mass is swept out by the pinch near the axis and also by the j x B force in the twisted field region surrounding the axis.