Numerical simulation of slow spheromak formation: Flux control by formation speed

Two-dimensional magnetohydrodynamic simulations of the Princeton S-1 Spheromak have been carried out for several formation speeds. It is found that the spheromak size and shape, and hence the confined poloidal and toroidal fluxes, are largely dependent upon the formation speed, provided this is moderately slow. Specifically, the total toroidal and poloidal fluxes in a spheromak increase as the formation speed is reduced. The role of externally driven reconnection as a cause for this dependence is discussed.