Computation of two-fluid flowing equilibrium of helicity-injected spherical torus plasma

A two-fluid flowing equilibrium of a helicity-injected spherical torus (HI-ST) plasma in the more realistic region, including a flux conserver and a coaxial helicity source, is numerically determined by using the combination of the finite difference and the boundary element methods. It is found from the numerical results that magnetic configurations change from the high-q HI-ST (safety factor q>1) with paramagnetic toroidal field and low-beta (volume average beta value, langbetarangap2%) through the helicity-injected spheromak and reversed-field pinch to the ultralow-q HI-ST (0<q<1) with diamagnetic toroidal field and high-beta(<beta>ap18%) as the external toroidal field at the inner edge regions decreases and reverses the sign. The effects of the ion flow on the MHD equilibrium configurations are discussed