Multifaceted asymmetric radiation from the edge of tokamak plasmas (MARFE): Pattern formation under nonlocal constraints

A simplified two‐dimensional nonlinear fluid model is developed to elucidate the basic mechanism of the formation of multifaceted asymmetric radiation from the edge of tokamak plasmas (MARFE). In the framework of a mixed Eulerian–Lagrangian description, the problem is reduced to a reaction‐diffusion‐type equation with nonlocality, which obeys the constraints of length constancy and mass conservation along the magnetic field. With sufficient radiative cooling, this model predicts formation of MARFE‐like plasma condensations from a variety of initial conditions.