Effect of Rotational Transform on Toroidal Confinement

A one-fluid simulation model has been used to investigate diffusion in a low-$\beta$ toroidal plasma. The plasma behavior exhibits two disjoint regimes as a function of rotational transform. Larger transform yields unshocked flow and effectively classical plasma loss. With a decrease of only a few percent in transform angle, an abrupt transition occurs and a standing shock appears, with an associated large increase in plasma loss.