A reduced MHD model for ITG-NTM interplay

A six-field reduced-MHD model is derived for plasma dynamics. The new model describes coherently both ion temperature gradient (ITG) mode and tearing mode and includes neoclassical effects. The model allows the construction of an energylike quantity with a linear pressure contribution that is conserved except for dissipative, finite Larmor radius, and neoclassical terms. This model may be used to study the nonlinear interaction between ITG microturbulence and neoclassical tearing mode, which is responsible for large-scale magnetic islands in tokamaks, and opens the way to a coherent description of turbulent impurity transport in magnetic islands.