Credit: Qian Teng, Princeton Plasma Physics Laboratory
The left figure shows a large, asymmetric magnetic island, which bulges on the inside (that is, the blue arrow is longer than the red), that can lead to a disruption and end a plasma discharge. The right figure shows the empirical scaling law of the density limit derived from experimental observations compared to the theoretical prediction, where the different symbols indicate different parameter assumptions (for example, different impurity concentrations). For all parameters, the predicted density limit agrees almost perfectly with the experimental scaling; that is ¯ne ≈¯nG